Pro: Droughts are Getting More Severe
From The Climate Reality Project:
Of all the ways climate change inflicts harm, drought is the one people worry about most, according to a Pew Research Center survey. And it’s not surprising – droughts have been drier and lasting longer in recent years thanks in part to climate change. In 2012, the central and western US was hit particularly hard when 81 percent of the country was living in abnormally dry conditions, causing $30 billion in damages and putting the health and safety of many Americans at risk.
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While droughts can have different causes depending on the area of the world and other natural factors, the majority of scientists have started to link more intense droughts to climate change. That’s because as more greenhouse gas emissions are released into the air, causing air temperatures to increase, more moisture evaporates from land and lakes, rivers, and other bodies of water. Warmer temperatures also increase evaporation in plant soils, which affects plant life and can reduce rainfall even more. And when rainfall does come to drought-stricken areas, the drier soils it hits are less able to absorb the water, increasing the likelihood of flooding – a lose-lose situation.
Source: https://www.climaterealityproject.org/blog/facts-about-climate-change-and-drought
Con: Droughts are Not Getting Worse
Currently, The United States is benefiting from fewer and less extreme drought events as the climate modestly warms. In fact, in 2017 and 2019, the United States registered its smallest percentage of land area experiencing drought in recorded history. The United States is undergoing its longest period in recorded history with fewer than 40 percent of the country experiencing “very dry” conditions. And even the U.N. IPCC reports with “high confidence” that precipitation has increased over mid-latitude land areas of the Northern Hemisphere (including the United States) during the past 70 years, while IPCC has “low confidence” about any negative trends globally.
On Page 90 – Chapter 12 of the UN IPCC Sixth Assessment Report. Emergence of Climate Impact Drivers (CIDs) under the “wet and Dry” section note that “Hydrological drought” is not detected as a result of climate change in the figure below. “Agricultural and ecological drought” is also absent.
The color corresponds to the confidence of the region with the highest confidence: white colors indicate where evidence of a climate change signal is lacking or the signal is not present, leading to overall low confidence of an emerging signal. See the key at the bottom for the meaning of all colors.
See also, https://www.ipcc.ch/site/assets/uploads/sites/2/2019/06/SR15_Chapter3_Low_Res.pdf, p. 191.
Real-world data show drought in the United States has become less frequent and severe as the climate has modestly warmed. Moreover, the United Nations reports “low confidence” about any negative trends globally. Droughts have always occurred, and they always will, so alarmists cannot claim that any droughts are necessarily caused by global warming. Instead, analysis of global and U.S. drought data show the droughts that have occurred recently are less frequent and severe than the droughts of the past several decades.
For example, the National Oceanic and Atmospheric Administration chart below shows that the United States is undergoing its longest period in recorded history without at least 40 percent of the country experiencing “very dry” conditions. Note also the peaks in drought around 1978, 1954, 1930, and 1900 are much larger than what the U.S. experienced in the 21st century and the late 20th century.
Figure 1: U.S. Wet and Dry Extremes
Figure 1: Percentage of United States experiencing “very wet” (in green) and “very dry” (in yellow) conditions. Source: National Oceanic and Atmospheric Administration: https://www.ncdc.noaa.gov/temp-and-precip/uspa/wet-dry/0.
And from NOAA:
Figure 2: Average Drought Conditions in the Contiguous 48 States, 1895–2015
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