Droughts

Although it may seem odd that we can have both floods and droughts as a result of global warming and climate change, but even though the air will be able to hold more water vapour as it gets warmer, the water will not fall as rain evenly around the globe. Generally speaking, areas which currently have rain can expect more of it, areas which get little can expect less of it.

Warmer temperatures can enhance evaporation from soil, making periods with low precipitation drier they would be in cooler conditions. Droughts can persist through a “positive feedback,” where very dry soils and diminished plant cover can further suppress rainfall in an already dry area. A changing climate can also alter atmospheric rivers (narrow streams of moisture transported in the atmosphere), which can especially disrupt precipitation patterns. A combination of shifting atmospheric rivers and warmer temperatures can also affect snowpack and melt, potentially decimating the water supply.

Agriculture: Droughts affect livestock and crops, including cornerstone commodities like corn, soybeans, and wheat. At the height of the 2012 drought, the U.S. Department of Agriculture declared a natural disaster over 2,245 counties, 71 percent of the United States. Globally, drought struck several major breadbasket regions simultaneously in 2012, adding to food price instability. In countries already facing food insecurity, cost spikes can lead to social unrest, migration, and famine.

Transportation: Droughts can affect water levels on rivers of commerce like the Mississippi. Transport barges need at least nine feet of water, and to maintain this level, the U.S. Army Corps of Engineers had to blast, dredge, and clear obstructions on a key stretch of the Mississippi in 2013. Also, drought and heat can buckle roadways. A 2011 drought in Texas caused $26 million in pavement distress.

Wildfires: Drought conditions and record heat have fueled damaging and sometimes deadly wildfires in the U.S. West. Millions of forested acres and thousands of homes have been lost over the past decade due to fires thriving in dry, stressed forests and the proximity of communities to fire-prone forests. The video below on the California wildfires explains in more detail just how droughts and global climate change can increase the frequency and sizes of wildfires.

Energy: Droughts can raise concerns about the reliability of electricity production from plants that require cooling water to maintain safe operations. Hydroelectric power may also become unavailable during droughts. When heat waves coincide with droughts, electricity demands can grow, compounding stress on the grid.

Please watch the video on the California wildfires, and how climate change is making the problem worse.