Future Looks Drier as Drylands Continue to Expand
A recent article in Reviews of Geophysics examined the areas of land globally that are classified as drylands and the impact of their growth on human communities.
Drylands currently constitute about 41 per cent of the Earth’s land surface and are home to more than 38 per cent of the world’s population. Drylands are particularly vulnerable to environmental change. In fact, the areas categorized as dryland have been increasing over recent decades, with further expansion set to continue under the influence of climate change. This will have knock-on effects on communities in regions on almost every continent, their crops and livestock, health and livelihoods.
A recent review article "Dryland climate change: Recent progress and challenges" in Reviews of Geophysics described recent progress in dryland climate change research. The journal’s editors asked two of the authors some questions about how and why dryland areas are changing, and asked them to give an overview of scientific research in this field.
What are “drylands” and where are they found?
Drylands are areas where the annual potential evapotranspiration greatly exceeds annual precipitation. Over drylands, the air is almost always “thirsty” for water but precipitation is not enough to meet this demand. The locations of drylands are determined mostly by atmospheric circulation and topography. They are primarily found in middle and low latitudes such as northern and southern Africa, Central and East Asia, southwestern North America, the west coast of South America, and much of Australia.
- How have dryland areas changed over recent decades?
- How will expanding drylands affect people?
- What are some of the recent major developments in drylands research?
- What are the major unsolved or unresolved questions in this field?
- Where are additional data or modeling efforts needed?
The answer to those questions and more about ...
The changes occurring in drylands are part of the dynamics of the global climate system so we need “big data” including high-quality ground-based observations and improved satellite retrieval products, as well as climatic proxies from paleoclimate research. Well-developed global and regional climate system models with more reasonable parameterization schemes suitable for dryland areas and so on are particularly required.
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