From the Latest Report of the IPCC Climate Change 2013: The Physical Science Basis Working Group 1 Contribution to the IPCC Fifth Assessment Report Dr David Wratt, NIWA, Wellington, New Zealand Yann Arthus-Bertrand / Altitude Presented at the Asahi World Environmental Forum, Tokyo, 30 Sept 2013
The IPCC: Policy-Relevant but not Policy-Prescriptive Assessments are to be on a comprehensive, objective, open and transparent basis IPCC reports should be neutral with respect to policy Review is an essential part of the IPCC process both peer review by experts and review by governments (from the Principles Governing IPCC Work)
Working Group and Synthesis Reports WG I: Physical science basis (27 September 2013) WG II: Vulnerability, impacts, adaptation options. (31 March 2014) WG III: Options for mitigating climate change. (12 April 2014) SYR (Synthesis Report) (1 Nov 2014) Presentation and distribution of the advance copy of the Synthesis Report to UNFCCC COP20: 3-14 Dec 2014 Picture: Report Covers from IPCC Fourth Assessment, 2007
The WG1 Report - Four Years of Hard Work Scoping meeting Venice, July 2009 209 Lead Authors and 50 Review Editors from 39 Countries Over 9,200 scientific publications cited Expert Review of First Order Draft + Expert and Government Review of Second Order Draft: 52,822 comments Approval Session Stockholm 23-26 September: Line by line approval of Summary for Policymakers
The WG1 Summary for Policymakers (SPM) - Some Key Findings
Warming in the climate system is unequivocal Since 1950 many changes have been observed that are unprecedented over decades to millenia
Each of the last three decades has been warmer than any preceding decade since 1850 (From Fig SPM.1)
Observed Changes - Atmosphere (From Fig SPM.1) Over this period (1901-2012) almost the entire globe warmed
In the mid-latitude areas of the Northern Hemisphere, precipitation has increased since 1900 (medium confidence) and since 1950 (high confidence) (From Fig SPM.3)
Over the last two decades: the Greenland and Antarctic ice sheets have been losing mass glaciers have continued to shrink almost worldwide Arctic summer sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent (From Fig SPM.3)
It is virtually certain that the upper ocean (0-700m) warmed from 1971 to 2010 (From Fig SPM.3)
The rate of sea level rise since the mid-19th century has been larger than during the previous two millenia (high confidence) (From Fig SPM.3)
Atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years (From Fig SPM.4)
The ocean has absorbed about 30% of the anthropogenic carbon, causing ocean acidification (From Fig SPM.4)
It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century (From Fig SPM.6)
(From Fig SPM.6)
Future Global and Regional Change Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system Most aspects of climate change will persist for many centuries even if emissions of carbon dioxide are stopped. Four future scenarios: Representative Concentration Pathways (RCPs) RCP8.5: Very high no mitigation scenario RCP6.0, RCP4.5: Medium stabilization scenarios RCP2.6: Mitigation scenario - very low forcing
Projections - Atmospheric Temperature (Fig SPM.8a)
Projections - Precipitation (Fig SPM.8b)
Projections - snow & ice (Fig SPM.8c)
Under all RCP scenarios the rate of sea level rise will likely exceed that observed during 1971-2010 (Fig SPM.9)
Further uptake of carbon by the ocean will increase ocean acidification (Fig SPM.8d)
Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions. 1,000 billion tons carbon (By 2011 we had used 530 billion tons)
Reflections on the Report Human influence on the climate system is clear Most aspects of climate change will persist for many centuries, even if emissions of carbon dioxide are stopped. Projected warming at end of 21st C compared to 1850-1900: For RCP8.5 About as likely as not to exceed 4 C For RCP2.6 67% probability to stay below 2 C We have a choice - the trillionth ton My view: Address adaptation capability, energy production and use Working Group 2 will assess vulnerability / impacts / adaptation options (March 2014); Working Group 3 Mitigation (April 2014).
Further Information www.climatechange2013.org Yann Arthus-Bertrand / Altitude