The Physical Science Basis: Overview of WGI Contribution
- 1. © Yann Arthus-Bertrand / Altitude Highlights of IPCC WG1 Report Prof Fredolin Tangang IPCC WG1 Vice-Chair 259 Authors from 39 Countries WGI Co-Chairs and TSU Team
- 3. Warming in the climate system is unequivocal Human influence on the climate system is clear Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions
- 4. Fig.SPM.1b Temperature Difference 1901 to 2012 based on trend (°C) Fig.SPM.2 Precipitation Trend (mm/yr per decade) © IPCC 2013© IPCC 2013 Warming of the climate system is unequivocal
- 5. Fig. SPM.3 Warming of the climate system is unequivocal
- 6. Historical GHG Emission The atmospheric concentrations of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) have increased to levels unprecedented in at least the last 800,000 years.
- 7. GHG Historical Record in Ice Cores --------------300 ppm------------ --------------200 ppm------------ 400 ppm IPCC (2007) Ice Cores
- 8. Humans are changing the climate Human Influence is Clear
- 9. Climate Models Responses to Various Forcings Natural CO2 forcing only Human Influence is Clear Natural + Anthropogenic
- 10. Earth has been in radiative imbalance, with more energy from the sun entering than exiting the top of the atmosphere, since at least circa 1970. It is virtually certain that Earth has gained substantial energy from 1971–2010. More than 90% of this extra heat is absorbed by the ocean (high confidence) Earth is in Radiative Imbalance
- 12. Projecting Future Climate Requires GHG Concentration Pathway For future climate projections, climate models require Emission Scenarios. Models in AR5 use Representative Concentration Pathway (RCP)
- 14. IPCC2013,Fig.SPM.8 Today we have a choice. 4.5°C world2°C world
- 15. IPCC AR5 Synthesis Report The window for action is rapidly closing 65% of our carbon budget compatible with a 2°C goal already used Amount Used 1870-2011: 515 GtC Amount Remaining: 275 GtC Total Carbon Budget: 790 GtC CO2 emissions in 2013: 9.9 GtC Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.