Common belief states that the dominant factor determining water scarcity in the next few decades will be population growth. However, according to a new study by Stony Brook University, it's climate change -- not population growth -- that plays the main role in predicting future exposure to extreme droughts.
The study published in Climatic Change: "The relative importance of climate change and population growth for exposure to future extreme droughts," looks at the future global and national populations' exposure to extreme drought, based on an ensemble of 16 climate models and UN population growth projections.
The results imply that cutting greenhouse gas emissions should be the primary policy response for decreasing the number of people exposed to future extreme droughts. Population growth, while playing an important role for populations' drought exposure in some countries, is a less significant force, one for which developing nations should not be held responsible.
Among the highlights:
•By the end of the century (2081-2100), the number of people exposed to extreme drought will increase by 426.6% relative to the present, under the business-as-usual emissions.
•Climate change alone is responsible for 59.5% of the increase.
•Population growth alone is responsible for 9.2% of the increase.
•Climate change and population growth combined effect (technically, "interaction") is responsible for 31.4%.
•129 countries will experience increase in drought exposure mainly due to climate change alone.
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