In an effort to understand how plants around the world will act in a warming climate, researchers have relied increasingly on experiments that measure how they respond to artificial warming. But a new study says that such experiments are underestimating potential advances in the timing of flowering and leafing four to eightfold, when compared with natural observations. As a result, species could change far more quickly than the experiments suggest, with major implications for water supplies, pollination of crops and ecosystems. The comparison, done by an interdisciplinary team from some 20 institutions in North America and Europe, appears this week in the leading journal Nature.
"Up to now, it's been assumed that experimental systems will respond the same as natural systems respondbut they don't," said coauthor Benjamin Cook, a climate modeler at the NASA Goddard Institute for Space Studies and Columbia University's Lamont-Doherty Earth Observatory. Elizabeth Wolkovich, who led the team as a postdoctoral fellow at the University of California, San Diego, said, "This suggests that predicted ecosystem changesincluding continuing advances in the start of spring across much of the globemay be far greater than current estimates based on data from experiments."
The timing of annual plant and animal life eventsthe study of which is known as phenology--has emerged as perhaps the most consistent and visible gauge of nature's response to rising temperature. Globally over the past century, land surfaces have warmed an average of about half a degree Celsius (1.25 degrees Fahrenheit), but some places, such as Alaska, are warming much more rapidly (there, about 1.8 degrees C, or over 3 degrees F). As a result, long-term historical records show that many plant species are flowering and leafing out days, or even weeks, earlier over recent decades. For instance, the meticulously recorded and celebrated blooming of Washington D.C.'s cherry blossoms
|Contact: Kim Martineau|
The Earth Institute at Columbia University