The 2002 North American drought left an extra 360 million tons of heat-trapping carbon in the air, equivalent to the pollution caused that year by 200 million U.S. cars, according to a study released this week by the National Oceanic and Atmospheric Administration. The prolonged drought cut by half the continent’s ability to absorb carbon dioxide, said the study. Most atmospheric scientists say increased carbon dioxide is the main reason the planet’s average temperatures are creeping up. NOAA used its powerful new modeling system CarbonTracker to analyze data. CarbonTracker found that in North America, humans released 1.9 billion metric tons of carbon into the atmosphere each year – through burning fossil fuels. Typically, forests, grasslands, crops and soil would be expected to absorb about one-third of those emissions in North America. But that natural ratio slumped in 2002 when the continent had one of its largest droughts in a century. Conditions over almost half of the United States were deemed ‘extreme’ or ‘exceptional.’ Vegetation and soil took up only 330 million metric tons of carbon, down from a yearly average of 650 million metric tons. Humans and other animals breathe in […]