Archives for category: Drought
indonesia_fires

(Photo by Martin Wooster.)

In September and October 2015, tens of thousands of fires sent clouds of toxic gas and particulate matter into the air over Indonesia. Despite the moist climate of tropical Asia, fire is not unusual at this time of year. For the past few decades, people have used fire to clear land for farming and to burn away leftover crop debris. What was unusual in 2015 was how many fires burned and how many escaped their handlers and went uncontrolled for weeks and even months.

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NASA Earth Observatory, March 2015

[yframe url=’http://www.youtube.com/watch?v=BaIJJ-btleM&feature=player_embedded’]
Ben Cook, a climatologist affiliated with NASA’s Goddard Institute for Space Studies (GISS) and Columbia University’s Lamont-Doherty Earth Observatory in New York City, highlighted new research that indicates the ancient Meso-American civilizations of the Mayans and Aztecs likely amplified droughts in the Yucatán Peninsula and southern and central Mexico by clearing rainforests to make room for pastures and farmland.

Converting forest to farmland can increase the reflectivity, or albedo, of the land surface in ways that affect precipitation patterns. “Farmland and pastures absorb slightly less energy from the sun than the rainforest because their surfaces tend to be lighter and more reflective,” explained Cook. “This means that there’s less energy available for convection and precipitation.”

NASA, December 2011

The record-breaking drought in Texas that has fueled wildfires, decimated crops, and forced the sale of cattle herds has also reduced levels of groundwater to the lowest levels observed in more than 63 years. Groundwater is moisture trapped in pores in the soil and in underground gaps in rock, often known as aquifers.

The map above depicts the amount of groundwater stored underground in the continental United States on November 28, 2011, as compared to the long-term average from 1948 to 2011. Deep reds reveal the most depletion, with deep blues representing aquifers and soils that are nearly full. The maroon shading over eastern Texas, for example, shows that the ground has been this dry less than two percent of the time between 1948 and the present.

At the end of November 2011, groundwater supplies were extremely depleted in more than half of Texas, as well as parts of New Mexico, Louisiana, Alabama, and Georgia. The northeastern states and the High Plains appear saturated with water heading into winter months.

Earth Observatory, November 2011