Scientists have shown how droughts are threatening the health of wetlands globally. They have shown the many physical and chemical changes occurring during droughts that lead to severe, and sometimes irreversible, drying of wetland soils.
A wetland is a distinct ecosystem that is flooded by water, either permanently or seasonally, where oxygen-free processes prevail. The primary factor that distinguishes wetlands from other land forms or water bodies is the characteristic vegetation of aquatic plants, adapted to the unique hydric soil.
Wetlands around the world are incredibly important for maintaining our planet's biodiversity and they store vast amounts of carbon that can help fight climate change.
Globally, wetlands cover an area greater than 12.1 million square kilometres and deliver in benefits such as for flood mitigation, food production, water quality improvement, and carbon storage.
Wetlands can suffer "water droughts" both from the effects of a drier climate, and also when excessive water is extracted or diverted that would normally flow into them.
The research describes how drought often leads to severe cracking and compaction, acidification, loss of organic matter, and enhanced greenhouse gas emissions.
Effects can be different in different soil types and different regions of the world. The spatial distribution of drought studies shows there has been limited assessment in a large number of regions, including south and central America, Africa, the Middle East, Asia and Oceania. Many of these regions are predicted to be vulnerable to drought impacts due to climate change.
At a global level, wet soils are highly vulnerable to the effects of climate change and need to be protected given the very high environmental and socio-economic values they support.