The climate negotiations are becoming more and more important in order to come up with an action plan for the Climate Agenda which came into being in 2015. The knowledge on scientific aspects of climate shifts are important when determining the action required across different places on earth. This is of course in addition to the action that is much needed regardless of the location. Therefore, we have recently been looking into the IPCC publications and the report recently published by Annual Reviews titled, “Recent Progress and Emerging Topics on Weather and Climate Extremes Since the Fifth Assessment Report of the Intergovernmental Panel on Climate Change”. This article focuses on discussing the precipitation extremes based on the facts highlighted in the above report.
The report indicates that the confidence level for the precipitation extremes not high enough to be satisfactory in regions of Central and South America, Asia, and Africa. Therefore, the uncertainties that come with this might lead to inaccurate and insufficient understanding of changes in monsoon behaviors. This indicates that there is a need for more reliable monsoon modelling. Institutions like Colorado State University (CSU) are looking in to integrate machine learning techniques for the climate models to better understand monsoon circulations.
Intermittent behavior of precipitation extremes is another concern and is studied to understand the nature of high precipitation events. Sri Lanka seems to observe high precipitation events in each year in recent years and specifically in 2011, 2014, 2015. 2016 and 2017 significant damages were reported. Another point to note is despite the 2018 precipitation was relatively less damaging for Sri Lanka, south-western Indian provinces were severely affected. More data extractions during these events through gauge observations, radar, and satellites would be highly useful for further research and modelling.
Another aspect to consider is sub daily precipitation extremes, the report claims that this was “insufficiently assessed in AR5 and SREX”. There are statistical studies from countries like Singapore and would be useful to incorporate. In Singapore's case, precipitation activity is influenced by the El Niño Southern Oscillation, but not during the North-East Monsoon season. During the La Niña phase, the precipitation is shifted towards the morning.
Post-AR5 there has been research into changes in extreme snowfall, which exhibit an overall tendency toward decreases in several metrics at both regional and continental scales. It would be interesting to look at the current winter in the Southern hemisphere and coming winter season in the northern hemisphere for further analysis. By observation we could state that in states like Colorado in USA, the snowfall has decreased over the years.