Climate change is increasing spatial variation in precipitation patterns and is expected to make wet regions wetter and dry regions drier in general although there could be a few exceptions. Precipitation averaged over the mid-latitude land areas of the Northern Hemisphere has increased since 1951, while other areas such as Southeast Asia and some parts of Africa have observed a decrease in precipitation.
Higher greenhouse gas concentrations would make regional variations even more pronounced. Under a high greenhouse gas concentration scenario, high latitudes and the equatorial Pacific region are likely to experience an increase in annual mean precipitation for the rest of the century. In contrast, in many mid-latitude and dry subtropical regions, the mean precipitation is likely to decrease. For instance, the Mediterranean region, which has already experienced an increase in droughts, may see increases in drought frequency and magnitude under a high greenhouse gas concentration scenario, which is associated with a warming level higher than 2°C.
With the spatial variation in precipitation patterns, some locations are likely to see an increase in the number of heavy precipitation events. The upward trends in heavy precipitation and discharge would pose greater risks of flooding in some river catchments. For instance, persistent high rainfall in the Yangtze River catchment in China caused severe flooding in 2020.
The shift in precipitation patterns and the projected increase in the frequency of floods and droughts in some countries directly affect energy supply and demand. For instance, increased seasonal and annual variability in rainfall, more frequent heavy rainfalls or severe droughts, can pose significant challenges to the operation and planning of hydropower systems. Thermal power plants that use freshwater as a coolant can be critically affected by the shift in precipitation patterns and droughts. Severe water shortages in India in 2016 due to droughts led to the shutdown of 18 power plants by limiting the availability of cooling water. In some countries, the potential application of new technologies, such as carbon capture, use and storage, may also be constrained due to the additional water intensity they add to power plants. The increasing frequency of extreme precipitation and its associated events, such as floods, soil erosion, landslides and rock falls, could also damage transmission and distribution systems. Droughts can also increase energy demand for water supply, requiring more energy for water pumping or desalination.
The increasing probability of extreme precipitation events, which is one of the major causes of flooding, is an added challenge for most IEA member and association countries. Indeed, 87% of IEA member and association countries already have a medium or high level of exposure to floods. Particularly, Thailand, China, India, Brazil, Indonesia, Hungary and Mexico are more exposed to floods than others. Certain countries in Scandinavia (Norway, Denmark and Finland) or with a small territory (Luxembourg and Singapore) are the least exposed to the risk of floods.
