Is Climate Change Shifting the Water Cycle?

Managing our water resources well for sustainability and becoming resilient in the face of increasing demands due to population growth and climate change impacts means that we need information on the current state of our water cycle.

The 2022 Global Water Monitor Consortium report brings together public and private public and private research and development organisations to provide information on precipitation, air temperature and humidity, soil water availability, river flows and water volumes in natural and artificial lakes. The report summarises trends in the water cycle and examines significant hydrological events in 2022.

According to the report, 2022 is the third La Niña year in a row, which intensified droughts in the Americas and the Horn of Africa while bringing devastating floods in Pakistan.

The following are the report’s key findings:

• The water cycle was dominated by warmer than average ocean waters in the western Pacific Ocean and cool waters in the east, combined with a negative Indian Ocean Dipole, with relatively warm sea water in the eastern and northern Indian Ocean and cool water in the west, resulting in a heatwave in south Asia early in the year and followed by powerful monsoon bring heavy than usual rains which caused floods and landslides in Pakistan, Afghanistan, India, Thailand, Cambodia, Australia and several other countries.
• Rainfall in the Americas, Africa and Central Asia was below average, intensifying drought conditions in the western USA, the centre of South America and the Horn of Africa.
• In western Europe and much of China, heatwaves and drought marked the summer of 2022, with rivers and lakes shrinking before returning to more average conditions later in the year.
• The last two decades have seen increased air temperatures and declining air humidity, increasing heat stress and water requirements for people, crops and ecosystems alike.

Below is a map from the Global Water Monitor 2022 report summarising the major water-related events in 2022.

The report findings show that the earth’s water cycle is changing. The air is getting hotter and drier, which means more droughts and wildfires.

Scientist warns that the rapidly changing weather patterns across the globe can bring “flash droughts”.

Cosmos reports that Professor Albert van Dijk from the Australian National University (ANU) Fenner School of Environment and Society and lead author of a new report on global water availability released today says flash droughts are “analogous to a flash flood” (Mannix, 2022).

“A flash drought is an unexpectedly rapid development of drought conditions,” Van Dijk says. This event is most noticeable in somewhat humid regions with a winter or cool season, like much of Europe.

Van Dijk adds that “much higher temperatures lead to more rapid drying and, especially, cause more and more severe bushfires”. He cites the 2019-20 bushfire on Australia’s east coast as an example.

Flash droughts can also impact ecosystems and crops that are accustomed to regular rainfalls, and as for nature, produce, and people – all will need more water to stay healthy, which compounds the problem, he says.