Current Evidence of Climate Change

*Numerous long-term changes in the climate have been observed, including extreme weather such as droughts, heavy precipitation, heat waves and the intensity of tropical cyclones.

* Trends towards more powerful storms and hotter, longer dry periods have been observed and are assessed in the IPCC’s Fourth Assessment Report. Warmer temperatures mean greater evaporation, and a warmer atmosphere is able to hold more moisture -- hence there is more water aloft that can fall as precipitation. Similarly, dry regions are apt to lose still more moisture if the weather is hotter; this exacerbates droughts and desertification.


Extra-strength weather
Droughts are becoming more severe as world temperatures increase.

* The frequency of heavy precipitation events has increased over most land areas. Significantly increased precipitation has been observed in eastern parts of North and South America, northern Europe and northern and central Asia. There is also observational evidence for an increase of intense tropical cyclone activity in the North Atlantic since about 1970.

*Drying has also been observed over large regions, i.e. the Sahel, the Mediterranean, southern Africa and parts of southern Asia.

* In Africa's large catchment basins of Niger, Lake Chad, and Senegal, total available water has decreased by 40 to 60 per cent, and desertification has been worsened by lower average annual rainfall, runoff, and soil moisture, especially in southern, northern, and western Africa.

* The Rhine floods of 1996 and 1997, the Chinese floods of 1998, the East European floods of 1998 and 2002, the Mozambique and European floods of 2000, and the monsoon-based flooding of 2004 in Bangladesh (which left 60 per cent of the country under water), are examples of more powerful storms.

The decline of winter

* Average Arctic temperatures increased at almost twice the global rate in the past 100 years. Temperatures at the top of the permafrost layer have generally increased since the 1980s by up to 3°C. In the Russian Arctic, buildings are collapsing because permafrost under their foundations has melted.

* Snow cover has declined by some 10 per cent in the mid- and high latitudes of the Northern Hemisphere since the late 1960s. Mountain glaciers and snow cover have declined in both hemispheres and widespread decreases in glaciers and ice caps have contributed to sea level rise. New data evaluated by the IPCC shows that losses from the ice sheets of Greenland and Antarctica have very likely contributed to sea level rise from 1993 to 2003. The average global sea level rose at an average rate of 1.8 mm per year between 1961 and 2003, but between 1993 and 2003 it rose by 3.1 mm per year.

* Almost all mountain glaciers in non-polar regions retreated during the 20th century. The overall volume of glaciers in Switzerland decreased by two-thirds.

Shifts in the natural world

* Scientists have observed climate-induced changes in at least 420 physical processes and biological species or communities.

* In the Alps, some plant species have been migrating upward by one to four meters per decade, and some plants previously found only on mountaintops have disappeared.

* In Europe, mating and egg-laying of some bird species has occurred earlier in the season -- in the United Kingdom, for example, egg-laying by 20 of 65 species, including long-distance migrants, advanced by an average of eight days between 1971 and 1995.

As computer models predict, severe storms are occurring more frequently.
* Across Europe, the growing season in controlled, mixed-species gardens lengthened by 10.8 days from 1959 to 1993. Butterflies, dragnonflies, moths, beetles, and other insects are now living at higher latitudes and altitudes, where previously it was too cold to survive.

IPCC scientists sound the alarm

It fell to scientists to draw international attention to the threats posed by global warming. Evidence in the 1960s and '70s that concentrations of carbon dioxide in the atmosphere were increasing first led climatologists and others to press for action. It took years before the international community responded.

* In 1988, an Intergovernmental Panel on Climate Change (IPCC) was created by the World Meteorological Organization and the United Nations Environment Programme (UNEP). This group issued a first assessment report in 1990 which reflected the views of 400 scientists. The report stated that global warming was real and urged that something be done about it.

* The Panel's findings spurred governments to create the United Nations Framework Convention on Climate Change. By standards for international agreements, negotiation of the Convention was rapid. It was ready for signature at the 1992 United Nations Conference on Environment and Development -- more popularly known as the "Earth Summit" -- in Rio de Janeiro.

* The IPCC now has a well-established role. It does not conduct its own scientific inquiries, but reviews worldwide research, issues regular assessment reports (there have now been four), and compiles special reports and technical papers.

The IPCC Assessment Reports

The preparation of the Assessment Reports on Climate Change is a key activity of the IPCC. The Fourth Assessment Report (AR4) was released in 2007, and it consists of four volumes: the three IPCC Working Groups (WGs) Reports and a Synthesis Report (SYR)." The process towards the Fifth Assessment Report is now underway.

* The IPCC's findings, because they reflect global scientific consensus and are apolitical in character, form a useful counterbalance to the often highly charged political debate over what to do about climate change. IPCC reports are frequently used as the basis for decisions made under the Convention, and they played a major role in the negotiations leading to the Kyoto Protocol, a second, more far-reaching international treaty on climate change that entered into force on 16 February 2005.

SYNTHESIS AND ASSESSMENT REPORT ON THE GHG INVENTORIES - 2009

SYNTHESIS AND ASSESSMENT REPORT ON THE GREENHOUSE GAS
INVENTORIES SUBMITTED IN 2009

This document contains Part I of the synthesis and assessment report, covering the 2009 submissions of the national GHG inventories of Annex I Parties, in accordance with the UNFCCC reporting guidelines adopted by decision 14/CP.11, including the 2009 inventory information voluntary reported under Article 7, paragraph 1, of the Kyoto Protocol, in accordance with decision 15/CMP.1.

Download the full document from: http://unfccc.int/resource/webdocs/sai/2009.pdf

Documentation to facilitate negotiations among Parties

Draft decisions on other issues identified in paragraph 49 (c) of
document FCCC/KP/AWG/2008/8


1. This addendum is a compilation of proposals by Parties for elements of decisions to be adopted by the Conference of the Parties serving as the meeting of the Parties to the Kyoto Protocol (CMP) at its fifth session. It has been prepared by the Chair of the Ad Hoc Working Group on Further Commitments for Annex I Parties under the Kyoto Protocol (AWG-KP), under his own responsibility, building on the work of the AWG-KP at its eighth session held in Bonn, Germany, from 1 to 12 June 2009, and
discussions at its informal meeting held in Bonn from 10 to 14 August 2009.
2. Proposals for elements of draft CMP decisions on emissions trading and the project-based mechanisms are contained in annex I. Options and proposals on how to address definitions, modalities, rules and guidelines for the treatment of land use, land-use change and forestry are contained in annex II. Proposals for elements of draft CMP decisions on greenhouse gases, sectors and source categories; common metrics to calculate the carbon dioxide equivalence of anthropogenic emissions by sources and removals by sinks; and other methodological issues are contained in annex III. Proposals for elements of draft CMP decisions on other issues are contained in annex IV.
3. Annexes I and III reflect limited modifications to the corresponding annexes to document FCCC/KP/AWG/2009/10/Add.3. Annexes II and IV are the same as the corresponding annexes to document FCCC/KP/AWG/2009/10/Add.3.


Download full report from: http://unfccc.int/resource/docs/2009/awg9/eng/10a03.pdf

Report of the review of the initial report of Croatia

This report covers the in-country review of the initial report of Croatia, coordinated by the United Nations Framework Convention on Climate Change (UNFCCC) secretariat, in accordance with “Guidelines for review under Article 8 of the Kyoto Protocol” (decision 22/CMP.1)

The review took place from 20 to 25 October 2008 in Zagreb, Croatia, and was conducted by the following team of nominated experts from the UNFCCC roster of experts: generalist – Ms. Riitta Pipatti (Finland); energy – Mr. Matej Gasperi (Slovenia); industrial processes – Ms. Barbara Muik (Austria); agriculture – Mr. Jorge Alvarez (Peru); land use, land-use change and forestry (LULUCF) – Mr. N.H. Ravindranath (India); and waste – Ms. Sirintornthep Towprayoon (Thailand). Ms. Pipatti and Ms. Towprayoon were the lead reviewers. In addition the expert review team (ERT) reviewed the national system, the national registry, and the calculations of Croatia’s assigned amount and commitment period reserve (CPR), and took note of the LULUCF parameters and the elected activities under Article 3, paragraph 4, of the Kyoto Protocol. The review was coordinated by Ms. Astrid Olsson and Mr. Javier Hanna (UNFCCC secretariat).


Download the full Report of the review of the initial report of Croatia:
http://unfccc.int/resource/docs/2009/irr/hrv.pdf

The Global Carbon Cycle

The global carbon cycle can be divided into two categories: the geological, which operates over large time scales (millions of years), and the biological - physical, which operates at shorter time scales (days to thousands of years) and as humans we meddle with both categories.

The global carbon cycle refers to the movements of carbon, as it exchanges between reservoirs (sinks), and occurs because of various chemical, physical, geological, and biological processes. The ocean contains the largest active pool of carbon near the surface of the Earth, but the deep ocean part of this pool does not rapidly exchange with the atmosphere. Below in the diagram, you can get some idea where and how carbon is stored in the whole Earth system. The global carbon cycle is usually thought to have four major carbon sinks interconnected by pathways of exchange. These sinks are;

* the atmosphere,
* the terrestrial biosphere (which usually includes freshwater systems and non-living organic material, such as soil carbon),
* the oceans (which includes dissolved inorganic carbon and living and non-living marine biota),
* and the sediments (which includes fossil fuels ).

Carbon exists in the Earth's atmosphere primarily as the gas carbon dioxide (CO2). Although it is a very small part of the atmosphere overall (approximately 0.04% and rising fast), it plays an important role in supporting life. Other gases containing carbon in the atmosphere are methane and chlorofluorocarbons (the latter is one we introduced and are still adding to). These are all greenhouse gases whose concentration in the atmosphere are increasing, and contributing to the rising average global surface temperature.



Global Carbon Cycle - Sinks and Storage

Carbon is taken up from Earth's system in several ways:

1. When the sun is shining, plants perform photosynthesis to convert carbon dioxide into carbohydrates, releasing oxygen in the process. Deforestation and land clearing pose serious problems to the carbon cycle, and obliterating this sink means more carbon is forced into the atmosphere.

2. At the surface of the oceans towards the poles, seawater becomes cooler and CO2 is more soluble. Cold ocean temperatures favour the uptake of carbon dioxide from the atmosphere whereas warm temperatures can cause the ocean surface to release carbon dioxide. With seas warming this means CO2 is not so easily absorbed, and remains in the atmosphere. This is coupled to the ocean's thermohaline circulation which transports dense surface water into the ocean's interior. During times when photosynthesis exceeded respiration, organic matter slowly built up over millions of years to form coal and oil deposits. All of these biologically mediated processes represent a removal of carbon dioxide from the atmosphere and storage of carbon in geologic sediments.

3. In upper ocean areas of high productivity, organisms form tissue containing carbon, and some also form carbonate shells or other hard body parts. Apart from trees in forests, phytoplankton in the Earth's oceans are very important organisms that soak up carbon. The seas contain around 36000 gigatonnes of carbon, and again and in warmer seas, organisms cannot produce carbonate shells at the same rate, and increasingly acidic seas dissolve shells, or make it difficult to create shelly material. This means of course that carbon dioxide is not being taken up as quickly through this process and more carbon remains in the atmosphere, propelling global warming.

4. As shelled organisms die, bits and pieces of the shells fall to the bottom of the oceans and accumulate as sediments. Only small amounts of residual carbon from plankton settle out to the ocean bottom but over long periods of time these represent a significant removal of carbon from the atmosphere.





Global Carbon Cycle - Sources

Carbon can be released back into the system in many different ways:

1. Through the respiration performed by plants and animals.

2. Through the decay of animal and plant matter. Fungi and bacteria break down the carbon compounds in dead animals and plants and convert the carbon to carbon dioxide if oxygen is present, or methane if not. The melting permafrost is releasing large amounts of methane, which contributes to global warming at a rate 21 more times than carbon dioxide.

3. Through combustion of biomass which oxidizes the carbon it contains, producing carbon dioxide (as well as other things, like smoke). Burning fossil fuels such as coal, petroleum products, and natural gas releases millions of tonnes of carbon that has been stored in the geosphere for millions of years. Fires also consume biomass and organic matter to produce carbon dioxide (along with methane, carbon monoxide, smoke), and the vegetation that is killed but not consumed by the fire decomposes over time adding further carbon dioxide to the atmosphere. Wildfires and forest fires are likely to increase as land masses dry out with higher rates of evaporation.

4. Production of cement. A component, lime, is produced by heating limestone, which produces a substantial amount of carbon dioxide, and impacting upon the global carbon cycle.

5. At the surface of the oceans where the water becomes warmer, dissolved carbon dioxide is released back into the atmosphere.

6. Volcanic eruptions and metamorphism are part of the global carbon cycle and release gases into the atmosphere. These gases include water vapour, carbon dioxide and sulphur dioxide. Find out how volcanic gases are measured here.


Latest Trends and Cause for Alarm!

There has been a decline in the efficiency of natural land and ocean sinks which soak up carbon dioxide (CO2) emitted to the atmosphere by human activities (anthropogenic) , according to findings published in late Oct 2007, in the Proceedings of the National Academy of Sciences of the US (PNAS).

The swift increase in atmospheric CO2 is due to faster economic growth coupled with a halt in carbon intensity reductions, in addition to natural sinks removing a smaller proportion of emissions from the air. Carbon intensity is the amount of carbon emitted to produce one dollar of global wealth.

The study’s lead author, Dr Pep Canadell, executive director of the Global Carbon Project, explained “Fifty years ago, for every tonne of CO2 emitted, 600kg were removed by natural sinks. In 2006 only 550kg were removed per tonne and that amount is falling.”

“In addition to the growth of global population and wealth, we now know that significant contributions to the growth of atmospheric CO2 arise from the slow down of natural sinks and the halt to improvements in carbon intensity.” The rise in growth in atmospheric CO2 is generating climate forcings that are bigger and sooner than expected. By altering the global energy balance, these mechanisms "force" the climate to change.

Taking Action

We already possess the scientific, technical, and industrial know how to solve the carbon and climate problem for the next half-century. A concept known as "carbon wedges" proposes to limit the human contribution to the global carbon cycle, in an effort to reduce global warming. Adoption of the wedge concept is essential if we are going to curb our extraordinary abuse of fossil based fuels.

Climate Change Temperature

Climate change temperature refers to how hot or cold the atmosphere, ocean or landmass is as measured by a thermometer as indicator by Celsius (C), Fahrenheit (F), or Kelvin (K)references.

Air temperature can be measured with a thermometer, invented by Italian mathematician Galileo Galilei about 1592. The basic design - a fluid-filled hollow glass bulb attached to a stem with a thread-like bore - is still used today. A traditional thermometer consists of mercury, or spirit in a glass tube and operates on the principle that the liquid expands more that the glass does when heated.

Thermometers are placed in specially designed shelters such as the Stevenson screen, a white, louvered box positioned about a metre above the ground. In 1718 Gabriel Daniel Fahrenheit (Germany) devised the Fahrenheit scale for measuring temperature. The Celsius temperature scale was formulated by Swedish astronomer Anders Celsius in 1742.

Digital electronic devices can also be used were the unit can record the max and min temperature reached and some units can store a series of data (a data logger) and others transmit an electronic signal measuring temperature back to a second temperature display on a PC or a base. These new probes can also be used to measure soil temperature.




The Electronic Maximum-Minimum Temperature Sensor (MMTS) have to a large extent replaced the old thermometer shown above. An electronic temperature sensor that replaces glass thermometers are housed in a white case to reflect sunlight and has vents all around so that the air flows freely over the temperature sensor inside. The idea is to measure the temperature in the shade, away from any direct effect of the sun. There are literally tens of thousands of devices like this measuring the temperature of air around the globe. Besides feeding into the bigger picture of climate change, these devices are important to our everyday life.


Upper Air Climate Change Temperature

The Radiosonde is a balloon-borne instrument platform with a battery powered device (new versions are little larger than a softdrink can) which relays information to a sensitive ground receiver at a tracking station near the launch site.

The radiosonde contains instruments capable of making direct in-situ measurements of air temperature, humidity and pressure with height, typically to altitudes of approximately 30 km. These observed data are transmitted immediately to the ground station by a radio transmitter located within the instrument package.

The ascent of a radiosonde provides an indirect measure of the wind speed and direction at various levels throughout the troposphere. Ground based radio direction finding antenna equipment track the motion of the radiosonde during its ascent through the air. The recorded elevation and azimuth information are converted to wind speed and direction at various levels by triangulation techniques.


Climate Change Temperature from Aircraft

NASA has for years maintained an orbiting fleet, a sensor web, of satellites that monitor the Earth's natural systems, inlcuding climate change temperature. As you can see in the movie below, the sensor web is in a constant state of motion, and each satellite is designed to look at a different aspect of the Earth.

NASA also maintains an airborne sciences division, which comprises a fleet of high altitude, high-tech scientific research aircraft. One of these is the DC-8. With aircraft such as this, scientists can get inside the clouds of a developing hurricane. Getting a good satellite overpass during the exact time and location of a developing hurricane is a matter of luck. But with an aircraft, you can pilot it or target it directly into the location where critical storm elements are coming together and you can stay there to study the atmospheric processes for hours.

Perhaps NASA's most unusual aircraft is the ER-2, a research version of the U-2 spy plane. Its long, narrow wings distinguish this aircraft. It flies at an altitude of 70,000 feet - so high that the single pilot must wear a pressurized spacesuit. From these great heights, the aircraft flies over the dome-like top of hurricanes, and measures amongst other things climate change temperature.

The Sea and Climate Change Temperature

Since the 1980s satellites have been increasingly utilised to measure sea surface temperature (SST) and have provided an enormous leap in our ability to view the spatial and temporal variation in SST. The satellite measurement is made by sensing the ocean radiation in two or more wavelengths in the infrared part of the electromagnetic spectrum which can then be empirically related to SST.

Also and since 2002, new measurements have come from an international collaboration called Argo, a global array of 3,000 free-drifting floats that measure temperature and salinity of the ocean’s upper 2,000 meters.

At 10-day intervals, the floats pump fluid into an external bladder and rise from 2,000 meters to the surface over a six-hour period while taking measurements. Satellites determine the floats’ positions when they surface and receive their transmitted data. The bladder then deflates and the float sinks to drift until the cycle repeats.


An Argo profiling float cycling through the water column. Graphic courtesy of National Oceanographic Centre Southampton



The Argo Floating
An Argo profiling float cycling through the water column. Graphic courtesy of National Oceanographic Centre Southampton

Climate Change

Climate change refers to the variation at a global or regional level over time. It describes the variability or average state of the atmosphere or average weather over time scales ranging from decades to millions of years. These variations may come from processes internal to the Earth, be driven by external forces (e.g. variations in sunlight intensity) or, most recently, be caused by human activities.

If you are not sure of the difference between 'climate' and 'weather', click on the link to find out: Climate-Weather.

No time to read all this? Visit Facts and Impacts for a one page summary, or listen to four scientists from Columbia University explain future climatic uncertainties. With Peter DeMenocal, Gavin Schmidt, Maxx Dilly and Klaus Lackner.

Just as weather patterns change from day to day, the climate changes too. This occurs naturally, driven by internal and external factors. However not all changes are due to natural processes, as we humans have also exerted our influence, which is called anthropogenic climate change.
Through widespread use of land, use of fossil fuels and the building of cities, we have changed our climate. The major technological and socioeconomic shift of the industrial era with reduced reliance on organic fuel, the accelerated uptake of fossil fuels, and broad scale deforestation, means we have contributed to the natural greenhouse effect.

The key areas for concern are those related to variability and extremes, not simply changed average conditions. There is an accumulating body of evidence of observed impacts relating to regional changes, and that these are having fearful effects on the world around us.

There are already people who have become climate refugees, and millions more are expected in the future. Temperatures across the globe are most certainly rising; the 1990s was the warmest decade in the last thousand years. Sea surface temperatures have increased 0.4-0.8°C (0.7-1.4°F) since the late 19 Century, and over the period 1961 to 2003, global ocean temperature has risen by 0.10°C (0.18°F) from the surface to a depth of 700 m.





The world has warmed 0.74°C in the past hundred years and scientists are clear that the world will get warmer this century due to further increases in greenhouse gas concentrations. Global average temperature is forecast to rise 4°C (7.2°F) toward the end of the 21st century.

Warming of a few degrees seems inconsequential compared with day to day, or seasonal variations in temperature. However, in global terms it is much larger than any of the climatic changes experienced during the past 10,000 years, since the rise of agriculture and civilisations. Although the Earth has seen many climatic changes during its 4.6 billion year history, the current changes are spurred by the human burning of fossil fuels.

In addition to warming of the Earth’s surface, there has been an increase in heatwaves, warming of the lower atmosphere and deep oceans. There are fewer frosts, permafrost is melting, glaciers are retreating and sea ice is decreasing. Sea levels have risen 10–20 cm and there is increased heavy rainfall in some regions, and less in others.

Climatic changes over recent decades have already affected some health outcomes. The World Health Organisation estimated, in its "World Health Report 2002", that climate change was estimated to be responsible in 2000 for approximately 2.4% of worldwide diarrhoea, and 6% of malaria in some middle-income countries. Epidemics of weather and climate-sensitive infectious diseases such as malaria and meningitis will have a devastating effect on human health and socio-economic development and severely overburden health systems in many parts of the world.

The Fourth Assessment Report released in 2007, by the Intergovernmental Panel on Climate Change (IPCC) stated that “there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities”. As seen below, The Report also shows why there is cause for deep concern:

Hydrology and Glaciers - Glaciers are retreating, and snow cover is decreasing (e.g. Davos in the Swiss Alps) with earlier snowmelt, and changing snow ecology. There is also reductions in the annual duration of lake and river ice.

Sea Ice - Declining sea-ice extent and thickness.

Animals - Poleward and elevational shifts in range, and alteration in species abundance (e.g. Sea Turtles ). Over a million species are predicted to become extinct by 2050 (e.g. Boyd's Forest Dragon, Cassowaries ). Changes in phenology (including earlier reproduction and migration), physiological and morphological adaptation.

Plants Change in abundance, diversity, and range, change in phenology (including earlier flowering), change in growth.

The previous Australian Government, whilst not signing the Kyoto Protocolhave acknowledged, “The projected global warming of a few degrees in the 21st century would occur at a time that is already one of the warmest for hundreds of thousands of years, with current levels of carbon dioxide not exceeded for the past 420,000 years, and not likely during the past 20 million years".

A few degrees of global warming will lead to more heat waves and fewer frosts. More wildfires and droughts are expected in some regions of the world with higher rainfalls and resultant flooding in other areas. Higher latitudes of the globe would receive more rainfall while middle latitudes, including parts of Australia, are likely to receive less. For these areas the changes will pose significant problems for water resource management.

Tropical hurricanes and cyclones may become stronger and sea levels will rise over the coming decades. Some low-lying coastal areas and islands are already feeling the effect, and will be more prone to inundation from storm surges.

Human induced climate change is another major stress in a world where natural and social systems are already experiencing pollution, increasing resource demands and unsustainable management practices.

Government's of the world are slowly responding, but is the response quick enough? At this stage the answer is, no. An international carbon price and developed carbon trading markets must be fast tracked. We must also move quickly to renewable energy as the source for our electricity and transport fuels.

IPCC Fouth Report

IPCC 4th Report

The Intergovernmental Panel on Climate Change (IPCC) was established by WMO and UNEP to assess scientific, technical and socio-economic information relevant for the understanding of climate change, its potential impacts and options for adaptation and mitigation. This site draws heavily on the reports published by the IPCC, and the science underpins pretty much every page.

There are three IPCC working groups, and each publish three separate reports that together make up the total report. The main report for each working group is generally over a hundred pages in length. The IPCC also has a summary document (about 20 pages) for each report. Below we have condensed these summaries to provide an overview of each section:

1. Working Group I - The Physical Science Basis

2. Working Group II - Impacts, Adaptation and Vulnerability

3. Working Group III - Mitigation of Climate Change


Comments by Tim Flannery

Australian of the Year Tim Flannery has said, the UN climate predictions on the consequences of global warming tread the "middle of the road" but will still provide a useful benchmark for the world to tackle climate change.

Professor Flannery, author of the book The Weather Makers said climate change was the most serious issue confronting humanity. The IPCC 4th Report "lays out a sort of middle of the road trajectory, which is alarming enough I can tell you, for this century," he told the ABC Radio National.

He also said that, temperatures could rise by much more than the IPCC 4th Report prediction of three degrees. "It could be worse than this - there's a 10 per cent chance of truly catastrophic rises in temperatures, so we're looking at six degrees or so", and "That would be a disaster for all life on earth. Three degrees will be a disaster for all life on earth."

"We will lose somewhere between two out of every 10 and six out of every 10 species living on the planet at that level of warming. "It will set in train a series of climate consequences that will run for a thousand years."

Tim Flannery said the clearest example of the IPCC's conservatism was its prediction the Arctic ice cap could disappear in summers by 2100.

"The actual trajectory we've seen in the Arctic over the last two years, if you follow that, that implies that the Arctic ice cap will be gone in the next five to 15 years. This is an ice cap that's been around for the last three million years," he said.

He went on to say that the predictions tell you a little bit about the conservatism of the IPCC 4th Report , "how rapidly the science is moving and how rapidly events in the real world are moving, far in advance I think of even the most sombre warnings by scientists working in this area."

Bali Action Plan

Download action plan documents:
http://unfccc.int/files/meetings/cop_13/application/pdf/cp_bali_action.pdf
http://www.undp.org/climatechange/docs/UNDP_BAP_Summary.pdf
Bali Action Plan Background

From 3 to 15 December 2007 the thirteenth conference of the parties to the United Nations Framework Convention on Climate Change (COP13) and the third Conference of the Parties serving as the Meeting of Parties to the Kyoto Protocol (COP/MOP3) were convened in Bali, Indonesia to discuss, among others, the future of the international climate regime after 2012.

In addition, the twenty-seventh sessions of the Subsidiary Body for Implementation (SBI) and Subsidiary Body for Scientific and Technological Advice (SBSTA) as well as the resumed fourth session of the Ad Hoc Working Group on Further Commitments for Annex I Parties under the Kyoto Protocol (AWG) took place. The major meetings were accompanied by numerous side events.

Bali Action Plan - Post-2012 Road Map

COP13 and COP/MOP3 succeeded in establishing a framework for negotiations to create an agreement that would replace the Kyoto protocol as of 2012. The final agreement reached by the international community in Bali, labelled by COP president Witoelar in its closing statement as a “breakthrough”, at the end of the day it may not represent what the EU has been asking for, namely a precise and concrete commitment to reduce anthropogenic greenhouse gas emissions of 25-40% by 2020, but still can be considered significant as it signs the return of the US in the negotiating process for the first time after the withdrawal from the Kyoto Protocol track of March 2001.

Still open and controversial is the question of how the requests of a more than ever fragmented international community will be combined in the near future. The Bali Action Plan, adopted as a COP13 Decision was accompanied by a series of Decisions adopted by COP/MOP3 and established a two-track process (Convention and Kyoto Protocol) aiming at the identification of a post-2012 global climate regime to be adopted by COP15 and COP/MOP5 in Copenhagen in 2009.

The Convention track included the establishment of an Ad Hoc Working Group on Long-Term Cooperative Action which will provide its conclusions on the “full, effective and sustained implementation of the Convention” by COP15 in 2009. The Kyoto Protocol track signed the continuation of the work of the AWG which is required to provide recommendations to COP/MOP5 for adoption of new commitments for Annex I Parties.

The Bali Action Plan did not introduce binding commitments to reduce greenhouse gas emissions but included the request for developed countries to contribute to the mitigation of global warming in the context of sustainable development. In addition, the Bali Action Plan envisaged enhanced actions on adaptation, technology development and on the provision financial resources, as well as measures against deforestation.

Post the Bali Conference (March 07) authors from the Wuppertal Institute (published in Climate Policy 8 (2008), pp. 91-95, www.earthscanjournals.com) analyse the results of the Conference. The analysis is here (pdf file).

****************************************************

Bali Action Plan - Advance unedited version

Decision -/CP.13 Bali Action Plan

The Conference of the Parties,

Resolving to urgently enhance implementation of the Convention in order to achieve its ultimate objective in full accordance with its principles and commitments,

Reaffirming that economic and social development and poverty eradication are global priorities,

Responding to the findings of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change that warming of the climate system is unequivocal, and that delay in reducing emissions significantly constrains opportunities to achieve lower stabilization levels and increases the risk of more severe climate change impacts,

Recognizing that deep cuts in global emissions will be required to achieve the ultimate objective of the Convention and emphasizing the urgency1 to address climate change as indicated in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change,

1. Decides to launch a comprehensive process to enable the full, effective and sustained implementation of the Convention through long-term cooperative action, now, up to and beyond 2012, in order to reach an agreed outcome and adopt a decision at its fifteenth session, by addressing, inter alia:

(a) A shared vision for long-term cooperative action, including a long-term global goal for emission reductions, to achieve the ultimate objective of the Convention, in accordance with the provisions and principles of the Convention, in particular the principle of common but differentiated responsibilities and respective capabilities, and taking into account social and economic conditions and other relevant factors;

(b) Enhanced national/international action on mitigation of climate change, including, inter alia, consideration of:

(i) Measurable, reportable and verifiable nationally appropriate mitigation commitments or actions, including quantified emission limitation and reduction objectives, by all developed country Parties, while ensuring the comparability of efforts among them, taking into account differences in their national circumstances;

(ii) Nationally appropriate mitigation actions by developing country Parties in the context of sustainable development, supported and enabled by technology, financing and capacity-building, in a measurable, reportable and verifiablemanner;

(iii) Policy approaches and positive incentives on issues relating to reducing emissions from deforestation and forest degradation in developing countries; and the role of conservation, sustainable management of forests and enhancement of forest carbon stocks in developing countries;

(iv) Cooperative sectoral approaches and sector-specific actions, in order toenhance implementation of Article 4, paragraph 1(c), of the Convention;

(v) Various approaches, including opportunities for using markets, to enhance the cost-effectiveness of, and to promote, mitigation actions, bearing in mind different circumstances of developed and developing countries;

(vi) Economic and social consequences of response measures;

(vii) Ways to strengthen the catalytic role of the Convention in encouraging multilateral bodies, the public and private sectors and civil society, building on synergies among activities and processes, as a means to support mitigation in a coherent and integrated manner;

(c) Enhanced action on adaptation, including, inter alia, consideration of:

(i) International cooperation to support urgent implementation of adaptation actions, including through vulnerability assessments, prioritization of actions, financial needs assessments, capacity-building and response strategies, integration of adaptation actions into sectoral and national planning, specific projects and programmes, means to incentivize the implementation of adaptation actions, and other ways to enable climate-resilient development and reduce vulnerability of all Parties, taking into account the urgent and immediate needs of developing countries that are particularly vulnerable to the adverse effects of climate change, especially the least developed countries and small island developing States, and further taking into account the needs of countries in Africa affected by drought, desertification and floods;

(ii) Risk management and risk reduction strategies, including risk sharing andtransfer mechanisms such as insurance;

(iii) Disaster reduction strategies and means to address loss and damage associated with climate change impacts in developing countries that are particularly vulnerable to the adverse effects of climate change;

(iv) Economic diversification to build resilience;

(v) Ways to strengthen the catalytic role of the Convention in encouraging multilateral bodies, the public and private sectors and civil society, building on synergies among activities and processes, as a means to support adaptation ina coherent and integrated manner;

(d) Enhanced action on technology development and transfer to support action on mitigation and adaptation, including, inter alia, consideration of:

(i) Effective mechanisms and enhanced means for the removal of obstacles to, and provision of financial and other incentives for, scaling up of the development and transfer of technology to developing country Parties in order to promote access to affordable environmentally sound technologies;

(ii) Ways to accelerate deployment, diffusion and transfer of affordable environmentally sound technologies;

(iii) Cooperation on research and development of current, new and innovative technology, including win-win solutions;

(iv) The effectiveness of mechanisms and tools for technology cooperation in specific sectors;

(e) Enhanced action on the provision of financial resources and investment to support action on mitigation and adaptation and technology cooperation, including, inter alia, consideration of:

(i) Improved access to adequate, predictable and sustainable financial resources and financial and technical support, and the provision of new and additional resources, including official and concessional funding for developing country Parties;

(ii) Positive incentives for developing country Parties for the enhanced implementation of national mitigation strategies and adaptation action;

(iii) Innovative means of funding to assist developing country Parties that are particularly vulnerable to the adverse impacts of climate change in meeting the cost of adaptation;

(iv) Means to incentivize the implementation of adaptation actions on the basis of sustainable development policies;

(v) Mobilization of public- and private-sector funding and investment, including facilitation of carbon-friendly investment choices;

(vi) Financial and technical support for capacity-building in the assessment of the costs of adaptation in developing countries, in particular the most vulnerable ones, to aid in determining their financial needs;

2. Decides that the process shall be conducted under a subsidiary body under the Convention, hereby established and known as the Ad Hoc Working Group on Long-term Cooperative Action under the Convention, that shall complete its work in 2009 and present the outcome of its work to the Conference of the Parties for adoption at its fifteenth session;

3. Agrees that the process shall begin without delay, that the sessions of the group will be scheduled as often as is feasible and necessary to complete the work of the group, where possible in conjunction with sessions of other bodies established under the Convention, and that its sessions may be complemented by workshops and other activities, as required;

4. Decides that the first session of the group shall be held as soon as is feasible and not later than April 2008;

5. Decides that the Chair and Vice-Chair of the group, with one being from a Party included in Annex I to the Convention (Annex I Party) and the other being from a Party not included in Annex I to the Convention (non-Annex I Party), shall alternate annually between an Annex I Party and a non- Annex I Party;

6. Takes note of the proposed schedule of meetings contained in the annex;

7. Instructs the group to develop its work programme at its first session in a coherent and integrated manner;

8. Invites Parties to submit to the secretariat, by 22 February 2008, their views regarding the work programme, taking into account the elements referred to in paragraph 1 above, to be compiled by the secretariat for consideration by the group at its first meeting;

9. Requests the group to report to the Conference of the Parties at its fourteenth session on progress made;

10. Agrees to take stock of the progress made, at its fourteenth session, on the basis of the report by the group;

11. Agrees that the process shall be informed by, inter alia, the best available scientific information, experience in implementation of the Convention and its Kyoto Protocol, and processes thereunder, outputs from other relevant intergovernmental processes and insights from the business and research communities and civil society;

12. Notes that the organization of work of the group will require a significant amount of additional resources to provide for the participation of delegates from Parties eligible to be funded and to provide conference services and substantive support;

13. Strongly urges Parties in a position to do so, in order to facilitate the work of the group, to provide contributions to the Trust Fund for Participation in the UNFCCC Process and the Trust Fund for Supplementary Activities for the purposes referred to in paragraph 12 above and to provide other forms of in kind support such as hosting a session of the group.

Material for this page, Bali Action Plan, sourced from: EEL Newsservice Special Edition, 18 December 2007, United Nations Climate Change Conference in Bali, http://www.eel.nl/index.asp?c_nr=1&sub_categorie=268&ssc_nr=1179&anker=EEL

Bali

After the 2007 United Nations Climate Change Conference on the island Bali in Indonesia in December, 2007, the participating nations adopted the Bali Roadmap (also known as the Bali Action Plan) as a two-year process to finalizing a binding agreement in 2009 in Denmark.

Cutting emissions

The nations acknowledge that evidence for global warming is unequivocal, and that humans must reduce emissions to reduce the risks of "severe climate change impacts". There was a strong consensus for updated changes for both developed and developing countries. Although there were not specific numbers agreed upon in order to cut emissions, many countries agreed that there was a need for "deep cuts in global emissions" and that "developed country emissions must fall 10-40% by 2020". [1]

Charges of hypocrisy

The December 2007 global warming conference in Bali contributed to global warming in the following ways:

* A November 25, 2007 article in Times Online reported that it was estimated that that year's conference would release the equivalent of 100,000 tons of carbon dioxide. [2]

* A December 18, 2007 article in the Sydney Morning Herald revealed new information that brought this total even higher. According to the article, a special custom air conditioning system was installed specifically for the conference. The air conditioning system used hydrochlorofluorocarbons, an outdated refrigerant gas that is especially bad for the problem of global warming. According to the article, the air conditioning used during the conference released the equivalent of 48,000 tons of carbon dioxide. The article stated, "... the refrigerant is a potent greenhouse gas, with each kilogram at least as damaging as 1.7 tonnes of carbon dioxide. Investigators at the Balinese resort complex at Nusa Dua counted 700 cylinders of the gas, each of them weighing 13.5 kilograms, and the system was visibly leaking." [3]

Forests

The nations pledge "policy approaches and positive incentives" to protect forests.

Adaptation

The nations opt for enhanced co-operation to "support urgent implementation" of measures to protect poorer countries against climate change impacts.

Technology transfer

The nations will consider how to facilitate the transfer of clean technologies from industrialised nations to the developing countries.

Timescales

Work on the Bali roadmap will begin as soon as possible. Four major UNFCCC meetings to implement the Bali Roadmap are planned for 2008, with the first to be held in either March or April and the second in June, with the third in either August or September followed by a major meeting in Poznan, Poland in December 2008. The negotiations process is scheduled to conclude in 2009 at a major summit in Copenhagen, Denmark.

Carbon Credits

Carbon Credits

There is an urgent need for countries to adopt a universal and global "carbon price" to arrest large scale greenhouse gas emissions. There is also much discussion about the best methods and incentives to control carbon output, that is, should there be a 'cap and trade' or tax combined with a voluntary carbon market or an emissions trading scheme to ensure emissions compliance?

As the world’s first cap-and-trade program for carbon dioxide emissions, the European Union’s Emissions Trading System (EU ETS) has attracted a lot of attention. Although this scheme has come under criticism from some quarters, the performance of the EU ETS cannot be evaluated without understanding that the first three years from 2005 through 2007 were a “trial” period. The EU ETS is also interesting because it provides some insights into the problems to be faced in constructing a global greenhouse gas emission trading system.

The personal approach discussed below differs from the larger industry scale Renewable Energy Certificates (RECs) and large scale carbon markets already mentioned. RECs are a tradable form of electronic currency and represent the environmental attributes of the power produced from renewable energy projects and are sold separate from commodity electricity. Although they differ between countries, under most programs, one REC would be equivalent to the environmental attributes of one MWh (Mega Watt hour) of electricity from a renewable generation source. More information on RECs is available by following the link above.



Personal Approach
By purchasing carbon credits you can help stimulate clean energy uptake and cut emissions contributing to global warming. Anyone can completely compensate their greenhouse gas emissions by going carbon neutral. Carbon neutral means that all your carbon dioxide (CO2) emissions are offset by carbon credits. You can purchase these for your home, car or air flights, compensating for all your personal CO2 emissions.


carbon footprints For individuals or households this is how it works: Firstly, a carbon calculator is used to work out your personal or family carbon footprint based on your annual energy activity. This calculation is the total of how much carbon dioxide you are releasing into the atmosphere through your activities. The amount of carbon dioxide you emit is then offset by the purchase of Carbon Credits.

There are quite a few retailers offering uncertified carbon offsets. You should avoid carbon offsets that don't come with a certification as they provide no guarantees that you are getting what you are paying for.

4Offsets.com are fighting global warming and provide a variety of ways for you to offset your greenhouse gas emissions and goGo Carbon Neutral. When you purchase carbon credits, you take responsibility for your contribution to climate change.


Planting Trees and Land Re-forestation
Another way to slow global warming is to plant more trees. Forests and trees breathe in carbon dioxide and by planting trees we create additional sinks, (C02 is sunk in the trees). Carbon storage in forests is part of a natural cycle, whereby some carbon is removed from the atmosphere and incorporated into the plant, and at the same time some carbon is released back to the atmosphere from the decomposition of litter and soil organic matter. The carbon dioxide absorbed by forests is tied up and kept out of the atmosphere. Deforestation at a global level has removed these precious carbon sinks, stopping the natural uptake of this gas. By planting more trees we can create forests that breathe in the carbon dioxide and breathe out our life giving oxygen.

Volunteer with tree planting groups and get involved for a few hours each year to reinvigorate yourself and our atmosphere. If you are unable to get out and plant, or spare the time, then purchase trees to be planted on your behalf.

By purchasing credits from an accredited company like Carbon Planet you are ensuring that the CO2 you produce is removed from the atmosphere and stored within a tree where it can no longer impact on the Greenhouse Effect.

Greenhouse Gas

We hear a lot about Greenhouse gas, but what is this? Why do these gases pose such a problem? Our atmosphere is a layer surrounding the earth held in place by gravity and primarily made up of Nitrogen (78%), Oxygen (21%), with water vapour and various gases making up the remainder.

It is on the 'remainder' that we will focus as it is the concentrations of these trace gases that cause the greenhouse gas problem. The trace gases are made up of Argon, Carbon Dioxide, Neon, Helium, Methane, Hydrogen, Nitrous Oxide and Ozone. (Follow the link to read more about the Ozone Hole) Human activities result in emissions of four principal greenhouse gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and the halocarbons (a group of gases containing fluorine, chlorine and bromine). All these gases have what is known as - Global Warming Potential , or GWP with some much higher than others.

Scientists now realise that the proportion of these gases has increased significantly over a few hundred years. The real increase began around the time of the Industrial Revolution. This is when we began to burn fossil fuels (coal) in large quantities to power our steam engines for industry, generate electricity, and heat our homes.

You can see from the graph below that carbon dioxide, nitrous oxide and methane have all increased significantly since the 1800s. Today the use of fossil fuel for power and electricity is thousands of times more than what it was in the 1800s.



The Greenhouse Blanket
Ok… You see how these gases have increased proportionally in our atmosphere, but perhaps you are thinking, so what?

To explain why these gases are termed greenhouse gases, we need to understand that during the day the earth absorbs heat from the sun, although much of this is radiated back out into space. The atmosphere surrounding our earth contains these gases, and acts like a blanket keeping some of the heat in. If there weren’t an atmospheric ‘blanket’ life may be impossible on Earth because everything would freeze at night, like some of the other planets or our moon.

This is where it gets a bit frightening! The fossil fuels we are burning in ever-increasing amounts contribute to higher concentrations of carbon dioxide, methane and nitrous dioxide (although oil reserves are running out ). These gases are called greenhouse gases because they effectively make the blanket around our globe thicker, trapping more heat and turning the globe into a green house.


The Big Issue
The problem with humans contributing so much carbon dioxide is that Earth's natural system is overwhelmed and can't keep up with the rate of our CO2 release. The natural carbon cycle is disrupted and Earth's carbon 'sinks' or places that carbon can be safely absorbed are either diminishing or saturated.

We have coined the terms 'Global Warming' and 'Climate Change', to describe what is happening. Global economic growth is driving higher carbon dioxide emissions and we really must manage the tremendous amounts of carbon dioxide we are emitting.

The Carbon Cycle section explains in more detail what the carbon 'sinks' or reservoirs are. The concept of sinks is extremely important in understanding the nature of this problem.

Making a serious dent in our emissions will require a number of measures such as renewable energy targets, measures to support energy efficiency, addressing energy market failures through feed-in tariffs and the continued support for commercialisation of clean energy technologies.

Atmospheric pollution is also behind the idea of Global Dimming(which is not truly global). In this theory, the particulates emitted when burning fossil fuels could be shielding us from the full impact of global warming.

For a quick one page summary on the Facts and Impacts of Climate Change go here


Greenhouse Gas Increasing
According to the US National Oceanic and Atmospheric Administration (NOAA), the amount of carbon dioxide (CO2) in the atmosphere increased by 19 billion tonnes in 2007. This is a rise of 0.6 per cent, lifting the concentration of the main greenhouse gas to 385 parts per million (ppm).

The measurements showed that levels of the second most abundant greenhouse gas, methane, jumped after being steady in recent years.

The rise in carbon dioxide from 280 ppm, along with increases in the other greenhouse gases, since the start of the Industrial Revolution is warming the planet changing our climate change beyond the natural cyclical variability.

The 2007 rise in global carbon dioxide is the third highest annual increase since atmospheric measurements began in 1958 and 20 per cent higher than the average of recent years.

The 19 billion tonne increase reflects an imbalance that has occurred in the planet’s carbon balance the net impact on atmospheric carbon dioxide from human and natural emissions on the one hand outweighing absorption from the air by oceans, vegetation and the soil. Since 2000, CO2 concentrations have been rising at 2 ppm every year compared to less than 1 ppm per year up to the 1960s.


Carbon Footprints
We all have a 'carbon footprint', which is a measure of the amount of carbon dioxide or CO2 emitted through the combustion of fossil fuels. This is directly related to the amount of natural resources consumed, and is increasingly used or referred to as a measure of environmental impact. The United States is certainly the biggest emitter, but with economies like China and India booming, the problem is set to expand exponentially. Below is a map showing tons of carbon dioxide emmited per country. How much carbon dioxide does your country contribute?

Global weather patterns are changing and greenhouse gas issues are affecting people... right now. You can make a difference, become informed, speak out, lobby politicians and get involved at a community level.

Measuring Climate Change

There is no single instrument measuring climate change. Instead there are thousands of measuring devices spread across the globe, on land, under the sea and in the air.

The climate system is a complex, interactive system consisting of the atmosphere, land surface, snow and ice, oceans and other bodies of water, and living things. The atmospheric component of the climate system is what we generally refer to as climate: climate is often defined as ‘average weather’. Climate is usually described in terms of the mean and variability of temperature, precipitation and wind over a period of time, ranging from months to millions of years (the classical period is 30 years, see weather and climate for more information on the difference between these two).

Countless empirical tests of numerous different hypotheses have now built up a massive body of Earth science knowledge. This repeated testing has refined the understanding of many aspects of the climate system, from deep oceanic circulation to stratospheric chemistry. Sometimes a combination of observations and models can be used to test planetary-scale hypotheses. For example, the global cooling and drying of the atmosphere observed after the eruption of Mt. Pinatubo provided key tests of particular aspects of climate models.

Climate science in recent decades has seen an increasing rate of advancement, particularly in field research and notably through the evolution of measuring climate change methodology and tools, including the models and observations that support and enable the research. During the last four decades, the rate at which scientists have added to the body of knowledge of atmospheric and oceanic processes has accelerated dramatically. As scientists incrementally increase the totality of knowledge, they publish their results in peer-reviewed journals.




There are a number of key factors in measuring climate change, and they are broadly categorised below. The range of instrumentation used to observe and measure climate is truly amazing. By following the links below you can see the types of instruments, and where they are used.

Temperature When measuring climate change this is a primary and can be measured or reconstructed for the Earth's surface, and sea surface temperature (SST).

Precipitation (rainfall, snowfall etc) offers another indicator of relative climate variation and may include humidity or water balance, and water quality.

Biomass and vegetation patterns may be discerned in a variety of ways and provide evidence of how ecosystems change to adapt to climate change.

Sea Level measurements reflect changes in shoreline and usually relate to the degree of ice coverage in high latitudes and elevations.

Solar Activity can influence climate, primarily through changes in the intensity of solar radiation.

Volcanic Eruptions, like solar radiation, can alter climate due to the aerosols that are emitted into the atmosphere and alter climate patterns.

Chemical composition of air or water can be measured by tracking levels of greenhouse gases such as carbon dioxide and methane, and measuring ratios of oxygen isotopes. Research indicates a strong correlation between the percent of carbon dioxide in the atmosphere and the Earth's mean temperature.



Combining Observation and Measurements

In understanding global climate changes it is necessary to combine many disciplines, including oceanography, meteorology, geomorphology, geology and paleoclimatology. As well as combining interdisciplinary studies, observations and measurements can be assembled over long time spans, using different measuring approaches. For example, the annual averages of the global mean sea level seen below are based on reconstructed sea level fields since 1870 (red), and the tide gauge measurements are since 1950 (blue) while the satellite altimetry is since 1992 (black). The units are in millimetres relative to the average for 1961 to 1990 and the error bars are at 90% confidence intervals.

By combining these three different approaches, scientists are able to build a clear picture of rising sea level that would not be possible if each was presented independently. You can also see with the introduction of accurate measuring, the confidence level for accuracy increases.


Sea levels



How Climate Knowledge Accumulates

Despite occasional major paradigm shifts, the majority of scientific insights, even unexpected insights, tend to emerge incrementally as a result of repeated attempts to test hypotheses as thoroughly as possible. Therefore, because almost every new advance is based on the research and understanding that has gone before, science is cumulative, with useful features retained and non-useful features abandoned. Active research scientists, throughout their careers, typically spend large fractions of their working time studying in depth what other scientists have done.

Superficial or amateurish acquaintance with the current state of a scientific research topic is an obstacle to a scientist’s progress. Working scientists know that a day in the library can save a year in the laboratory when measuring climate change.

Good science questions competing assertions about climate change. For example, can the statement under consideration, in principle, be proven false? Has it been rigorously tested? Did it appear in the peer-reviewed literature? Did it build on the existing research record where appropriate? If the answer to any of these questions is no, then less credence should be given to the assertion until it is tested and independently verified.



Uncertainties in Measuring Climate Change

The history of the centuries-long effort to document and understand climate change is often complex, marked by successes and failures, and has followed a very uneven pace. Testing scientific findings and openly discussing the test results have been the key to the remarkable progress that is now accelerating in all domains, in spite of inherent limitations to predictive capacity. Climate change science is now contributing to the foundation of a new interdisciplinary approach to understanding our environment. Consequently, much published research and many notable scientific advances have occurred in the last few decades, including advances in the understanding and treatment of uncertainty.

Uncertainties can be classified in several different ways according to their origin. Two primary types are ‘value uncertainties’ and ‘structural uncertainties’. Value uncertainties arise from the incomplete determination of particular values or results, for example, when data are inaccurate or not fully representative of the phenomenon of interest. Structural uncertainties arise from an incomplete understanding of the processes that control particular values or results, for example, when the conceptual framework or model used for analysis does not include all the relevant processes or relationships.

Uncertainties associated with ‘random errors’ have the characteristic of decreasing as additional measurements are accumulated, whereas those associated with ‘systematic errors’ do not. In dealing with climate records, scientists give considerable attention to the identification of systematic errors or unintended biases arising from data sampling issues and methods of analysing and combining data.

Fortunately, science is inherently self-correcting; incorrect or incomplete scientific concepts ultimately do not survive repeated testing against observations of nature.

Page based on 2007 IPCC Fourth Report.