The picture below shows Pinyon pine forests in New Mexico – and the progressive consequence of the large drought that hit western North America between 2000-2004. The left image is from 2002 and already shows some browning of pine trees halfway through the drought. The right image was taken two years later and shows an ecological threshold has been passed, with only surviving shrub vegetation.

During the drought that affected large parts of Canada, the US and Mexico natural carbon sequestration was cut in half and a lot of forests and other vegetation died.

A group of 10 American climate scientists have investigated the event and conclude it was the worst drought in 800 years. But don’t consider it an extreme, consider it the norm.

Photo credit: Craig D. Allen, USGS.

According to their publication in the August edition of Nature Geoscience, for the western part of North America this may become the new ‘climate normal’ and by the end of this century the drought of 2000-2004 is actually thought to represent a wet extreme.

The study was led by the Northern Arizona University and scientists from the University of Colorado, University of California at Berkeley, University of British Columbia, San Diego State University, and other institutions contributed.

© Rolf Schuttenhelm | www.bitsofscience.org