http://www.climatechange2013.org/
27 September 2013: The IPCC Fifth Assessment Report (AR5) Summary for Policymakers following the Twelfth Session of Working Group I (WGI-12) held from 23 to 26 September 2013 in Stockholm, Sweden. The full report by the Intergovernmental Panel on Climate Change (IPCC) is so long that it will be released in three parts during the course of the year. Over 600 scientists were involved.
United Nations officials have called for a global response to combat climate change, following new findings by a scientific panel stating it is “extremely likely” that humans have been the dominant cause of unprecedented global warming since 1950.
“The heat is on. Now we must act,” Secretary-General Ban Ki-moon said in a video message to the launch of the report of the UN-backed Intergovernmental Panel on Climate Change (IPCC).
“This new report will be essential for Governments as they work to finalize an ambitious, legal agreement on climate change in 2015,” Mr. Ban said. “The goal is to generate the political commitment to keep global temperature rise below the agreed 2-degree Celsius threshold.”
The IPCC report, released today in Stockholm, Sweden, calls global warming “unequivocal,” and confirms that there is a 95 per cent probability that most of the warming since 1950 has been caused by human influence.
The report stresses that evidence for this has grown “thanks to more and better observations, an improved understanding of the climate system response and improved climate models.”
“The IPCC report demonstrates that we must greatly reduce global emissions in order to avoid the worst effects of climate change,” said the Secretary-General of the World Meteorological Organization (WMO), Michel Jarraud. “It also contains important new scientific knowledge that can be used to produce actionable climate information and services for assisting society to adapt to the impacts of climate change.”
In its report, the IPCC notes that continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. It adds that limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.
“Climate change is a long-term challenge but one that requires urgent action, not tomorrow but today and right now, given the pace and the scale by which greenhouse gases are accumulating in the atmosphere and the rising risks of a more than 2-degree Celsius temperature rise,” said the Executive Director of the UN Environment Programme (UNEP), Achim Steiner.
To add momentum to the global response, Mr. Ban intends to convene a Climate Summit in September 2014 for leaders at the highest level – from government, business, finance, civil society and academia.
“As the results from the latest and best available science become clearer, the challenge becomes more daunting, but simultaneously the solutions become more apparent. These opportunities need to be grasped across society in mutually reinforcing ways by governments at all levels, by corporations, by civil society and by individuals,” said the Executive Secretary of the UN Framework Convention on Climate Change (UNFCCC), Christiana Figueres.
Under the UNFCCC, governments have agreed to limit the global temperature rise to 2 degrees Celsius to avoid the worst impacts of climate change. They have also agreed to assess the adequacy of this limit and progress towards this goal using the best science, including the IPCC report.
“Thankfully, momentum to fight climate change is building. We know that success is possible. We have the technology, funding and ability to respond. The many successes at domestic, international and private sector levels to build a low-carbon society shine light on the way forward, but we do need to quickly go to scale,” Ms. Figueres added.
It has been six years since the IPCC, which brings together the world’s leading climate scientists and experts, released its previous report. Back then, scientists stated it was “very likely” that humanity’s emissions of carbon dioxide, methane, nitrous oxide and other greenhouse gases have caused most of the global temperature rise observed since the mid-20th century.
Download the IPCC Fifth Assessment Report
PDF of the summary for policy makers is here.
Media response to the IPCC 5th Assessment Report
The ABC’s Media Watch hosted by Paul Barry on 23 September 2013, uncovered a disinformation campaign by numerous media outlets in the lead up to the IPCC AR5 report.
Learn about the Abbott Government’s response here via ABC News.
The Guardian’s full coverage and reaction is here.
For an exhaustive chronological account of the global response to the IPCC report check out this Guardian environment blog.
The Climate Council (previously the Climate Commission) has published a 16 page summary of the main points in the report here and the Council has released the following infographic.
Headline Statements from the Summary for Policymakers
Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.
Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. In the Northern Hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1400 years (medium confidence).
Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (high confidence). It is virtually certain that the upper ocean (0−700 m) warmed from 1971 to 2010, and it likely warmed between the 1870s and 1971.
Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent (high confidence).
The rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence). Over the period 1901–2010, global mean sea level rose by 0.19 [0.17 to 0.21] m.
The atmospheric concentrations of carbon dioxide (CO2), methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. CO2 concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification.
Total radiative forcing is positive, and has led to an uptake of energy by the climate system. The largest contribution to total radiative forcing is caused by the increase in the atmospheric concentration of CO2 since 1750.
Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.
Climate models have improved since the AR4. Models reproduce observed continental-scale surface temperature patterns and trends over many decades, including the more rapid warming since the mid-20th century and the cooling immediately following large volcanic eruptions (very high confidence).
Observational and model studies of temperature change, climate feedbacks and changes in the Earth’s energy budget together provide confidence in the magnitude of global warming in response to past and future forcing.
Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. This evidence for human influence has grown since AR4. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.
Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system.
Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.
Global surface temperature change for the end of the 21st century is likely to exceed 1.5°C relative to 1850 to 1900 for all RCP scenarios except RCP2.6. It is likely to exceed 2°C for RCP6.0 and RCP8.5, and more likely than not to exceed 2°C for RCP4.5.
Warming will continue beyond 2100 under all RCP scenarios except RCP2.6. Warming will continue to exhibit interannual-todecadal variability and will not be regionally uniform.
Changes in the global water cycle in response to the warming over the 21st century will not be uniform. The contrast in precipitation between wet and dry regions and between wet and dry seasons will increase, although there may be regional exceptions.
The global ocean will continue to warm during the 21st century. Heat will penetrate from the surface to the deep ocean and affect ocean circulation.
It is very likely that the Arctic sea ice cover will continue to shrink and thin and that Northern Hemisphere spring snow cover will decrease during the 21st century as global mean surface temperature rises. Global glacier volume will further decrease.
Global mean sea level will continue to rise during the 21st century. Under all RCP scenarios the rate of sea level rise will very likely exceed that observed during 1971–2010 due to increased ocean warming and increased loss of mass from glaciers and ice sheets.
Climate change will affect carbon cycle processes in a way that will exacerbate the increase of CO2 in the atmosphere (high confidence). Further uptake of carbon by the ocean will increase ocean acidification.
Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond. Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped. This represents a substantial multi-century climate change commitment created by past, present and future emissions of CO2.