The Intergovernmental Panel on Climate Change (IPCC) issued a Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) this week. The report, which is nearly 600 pages long, was produced by 220 authors from 62 countries.
The report begins by examining changes to extreme weather events since 1950. According to the authors, it is “very likely” that there has been an overall decrease in the number of cold days and nights, and that the overall number of warm days and nights has increased.
It is “likely” that anthropogenic influences (human activity) has led to the warming at global scales.
There is “medium confidence” that anthropogenic influences have contributed to the intensification of extreme precipitation events at global scales.
However, there is “low confidence” for attribution of any detectable changes in tropical cyclone activity to human influences. Part of the low confidence has to do with the fact that the hurricane record is not very extensive prior to the use of satellites.
The new report also acknowledges an increase in losses due to extreme weather. However, it primarily attributed the losses to an increase in exposure of people and assets. Still, the IPCC says climate change should not be totally excluded from the equation.
The Future: Temperatures
According to SREX, it is “virtually certain” that there will be an increase in the frequency and magnitude of warm daily temperature extremes and a decrease in cold extremes during the 21st century on the global scale.
It is considered “very likely” that the length, frequency, and/or intensity of the warm spells will also increase. For example, the report expects a 1 in 20 year hottest day to become a 1 in 5 year hottest day by the end of the century.
The Future: Precipitation & Storms
The authors say it is “likely” that the frequency of heavy precipitation will increase, and that the average maximum wind speed in tropical cyclones will increase.
While tropical systems may boast stronger winds, climate experts say it is also “likely” that the number of tropical cyclones will decrease, or remain largely unchanged this century.
The IPCC also maintains that it is “very likely” that mean sea level rises will continue, enhancing the risk of storm related flood episodes along the coast.
It is important to note that the IPCC chooses its words very carefully. For example:
“Virtually Certain”: 99-100% confidence
“Very Likely”: 90-100% confidence
“Likely”: 66-100% confidence