A new massive data set of 1,588 wild plants on four continents show that flowering and leaving advances by on average 4 to 5 days with every one degree Celsius warming. The information was published in the May 2nd issue of Nature. http://www.nasa.gov/topics/earth/features/early-bloom.html.
Gardeners around the USA will not be surprised by this latest collection of data, as they have seen earlier blooming and leafing in most parts of the USA over the last 60 years. Amazing and depressing should be the only reaction to the fact that some continue to deny the fact of warming, despite the massive evidence that the rising concentrations of heat trapping gas are raising temperatures and changing the seasons.
The newly gathered empirical data also indicates that the warming experiments being run to project the impact of warming are understating significantly the impact of warming on leafing and flowering dates. Indeed, as more data gathers, the trend in climate science is to find scientists have understated changes and risks, rather than overstated changes and risks. Sea level rise is just one such important example.