Climate change: IPCC projection for the future
The Intergovernmental Panel on Climate Change (IPCC) has published a report entitled "Climate Change 2021: The Physical Science Basis", which forms part of its Sixth Assessment Report (AR6). This report contains basic global data regarding both the current situation in terms of climate change and the outlook for the future, and for governments, international institutions, companies, and nonprofit organizations alike it is likely to form the basis of their understanding of climate change. It is also likely to form the basis of the discussions carried out at COP26 (the 26th United National Climate Change Conference), which is scheduled to start on October 31 this year.
The key points of the latest IPCC report are as follows.
1. Report states for the first time that it is "unequivocal" that human behavior has had an effect on climate
The IPCC's previous Assessment Report (AR5, published in 2013) simply said this was "extremely likely". The first Assessment Report (AR1, published in 1990) said that there was a risk of climate change occurring, but this was stated with increasing confidence in each successive report.
2. Timing of 1.5C rise in global average temperature (versus pre-industrial average) brought forward ten years
The previous forecast was that the increase in the global average temperature versus the preindustrial average would reach 1.5C in 2031-2050. The latest report brings the timing of this forward by ten years to 2021-2040.
3. Average global temperature will continue to rise through to the middle of the 21st century even if net zero emissions are achieved in 2050
The report sets out five scenarios for greenhouse gas emissions. Even in the scenario involving the greatest reduction in greenhouse gas emissions (with CO2 emissions volume reaching net zero around 2055), the average global temperature is predicted to rise by around 1.6C (versus preindustrial average) by the middle of the 21st century.
4. It will take from one hundred to several thousand years to reverse non-temperature changes (rise in sea levels)
The global average temperature will fall gradually if CO2 emissions turn negative. However, it will take some time for sea levels, which have risen, and the oxygen concentration of sea water, which has fallen, to return to their pre-industrial averages. It is also possible that the melting of ice sheets will not be reversed and that sea levels will remain at their higher levels.
5. Carbon budget of 300-400bn tonnes for 1.5C rise in global average temperature versus pre-industrial average
The carbon budget is the additional permitted volume of CO2 emissions corresponding to a particular target for the rise in the global average temperature. The IPCC report says the remaining CO2 emissions framework for a 1.5C increase in the global average temperature, with a probability of 67-83%, is 300-400bn tonnes. As CO2 emissions have been running at around 33bn tonnes a year recently, this means that there are only just over 10 years left in the carbon budget.
What is the IPCC?
Created in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), the objective of the IPCC is to provide governments at all levels with scientific information that they can use to develop climate policies. The IPCC is an organization of governments that are members of the United Nations or WMO and currently has 195 members.
The IPCC is divided into three Working Groups and a Task Force. Working Group I deals with The Physical Science Basis of Climate Change, Working Group II with Climate Change Impacts, Adaptation and Vulnerability and Working Group III with Mitigation of Climate Change. The main objective of the Task Force on National Greenhouse Gas Inventories is to develop and refine a methodology for the calculation and reporting of national greenhouse gas emissions and removals.
Summary from ESG research "IPCC report sets out 'almost certain future'" published on August 13, 2021