I was just reading an article about the agricultural drought in the southern Horn of Africa, and it seems they attribute it largely to warmer temperatures, rather than changes in precipitation.
https://www.worldweatherattribution....orn-of-africa/
They are describing it as an agricultural drought, which is different from a meteorological drought, which only takes into account whether there has been less precipitation than usual. Agricultural droughts also take into account evaporation and plant transpiration rates, which are higher under warmer temperatures.
According to the article, due overwhelmingly to warmer temperatures, the current drought is only a 1 in 26 year event, whereas in a 1.2C cooler world, it would be 100x rarer (a 1 in 2600 year event).
The horn of Africa has warmer a bit less than other parts of the world such as the northern latitudes, so the warming vs pre-industrial has been less than 1C.
They say that potential evapotranspiration (PET) in this part of Africa would be around 3700mm over an average year currently, compared to around 3050-3100mm/year in the 1.2C cooler global climate.
20% higher PET rates just from a temperature increase of probably less than 1C (like 26C to 27C annual mean or so)? Does this seem right? If true, then I would think PET increases should be the biggest concern with climate change, rather than changes in precipitation patterns, tornadoes, sea levels, etc.
Besides temperature, other factors that affect PET include sunlight, with cloudier weather reducing PET, relative humidity (lower humidity should raise PET), and carbon dioxide (higher levels reduce PET). Also vegetation changes, both due to human driven land use changes and plants changing on their own can affect PET - you can get more drought tolerant plants (different species), which often grow less vigorously, but consume less water, and plants of a single species can also adapt by going partially/fully dormant, reducing their leaf area (dropping leaves, growing new leaves that are smaller), although these vegetative changes would also come with a change in biological/agricultural productivity.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
