Background
The authors write that "flowering times are well-documented indicators of the ecological effects of climate change and are linked to numerous ecosystem processes and trophic interactions," noting that "dozens of studies have shown that flowering times for many spring-flowering plants have become earlier as a result of recent climate change." But they say that "it is uncertain if flowering times will continue to advance as temperatures rise."

What was done
In an effort designed to explore - and hopefully reduce - this uncertainty, Ellwood et al. say they "used long-term flowering records initiated by Henry David Thoreau in 1852 and Aldo Leopold in 1935 to investigate this question," capitalizing on the fact that record-breaking temperatures were recorded in the spring of 2010 and 2012 in Massachusetts (USA) and the spring of 2012 in Wisconsin (USA).

What was learned
The five U.S. researchers indicate that these record-breaking spring temperatures of 2010 and 2012 "resulted in the earliest flowering times in recorded history for dozens of spring-flowering plants of the eastern United States," and they also state that "these dramatic advances in spring flowering were successfully predicted by historical relationships between flowering and spring temperatures spanning up to 161 years of ecological change." In addition, they say "there is no indication that the 47 spring flowering plants we studied are delayed in their flowering by insufficient photoperiod or winter chilling requirements," noting that "these plants continue to flower earlier apparently in direct response to increasingly warmer mean spring temperatures."

What it means
Ellwood et al. conclude that "these results demonstrate that numerous temperate plant species have yet to show obvious signs of physiological constraints on phenological advancement in the face of climate change," which in this case is in the face of a global warming that climate alarmists characterize as the most dramatic of the past one to two millennia. This fact, in the words of the five scientists, "strongly suggests that most of these plants have not yet reached a physiological threshold," where such a relation might be expected to no longer hold true, to which we add: so far, so good ... so really good!