Plants' Response to Global Warming Severely Underestimated

A collaboration of researchers in the United States has just put together a major archive of historical observations covering the time of the year when plants leaf out and flower. The research demonstrates that this occurs sooner with each passing year.

This indicates that past studies have severely underestimated the response that vegetation will display when faced with the higher temperatures brought on by global warming and climate change. The conclusion belongs to warming experiments conducted in controlled conditions.

Such experiments are led in environments where researchers control all conditions, including soil moisture, ambiance temperature, sunlight amount and so on. These efforts are conducted so that the response of plants to global warming can be assessed, and introduced in computer models.

The latter are used to figure out how the world will change as average temperatures increase. In past studies, warming experiments provided some indicators of how plants would react to higher temperatures, but the new investigation demonstrates that previous values have severely underestimated these responses.

Details of the new investigation were published in the May 2 issue of the top journal Nature. One of its most important conclusions is that the very methodology used to conduct warming experiments at this time may need to be thought over and improved.

“This suggests that predicted ecosystem changes – including continuing advances in the start of spring across much of the globe – may be far greater than current estimates based on data from warming experiments,” scientist Elizabeth Wolkovich explains.

“The long-term records show that phenology is changing much faster than estimated based on the results of the warming experiments. This suggests we need to reassess how we design and use results from these experiments,” she adds.

Wolkovich led the interdisciplinary team of scientists that conducted this investigation while a postdoctoral fellow at the University of California in San Diego (UCSD). She worked closely with expert Benjamin Cook on the study.

Cook holds joint appointments, at the NASA Goddard Institute for Space Studies (GISS) and Columbia University, in New York.

“Continuing efforts to improve the design of warming experiments while maintaining and extending long-term historical monitoring will be critical to pinpointing the reasons for the differences, and will yield a more accurate picture of future plant communities and ecosystems with continuing climate change,” Wolkovich concludes.