Experiments that try to simulate global warming’s impact on
plants badly underestimate what happens in the real world,
according to a study published on Wednesday in the journal
Nature. The investigation backs anecdotal evidence from farmers
and gardeners, especially in the northern hemisphere, who say
seasonal plants are stirring into life far earlier than in the
past. Artificial experiments into global warming usually entail
encasing a plant in an open-top greenhouse-like chamber, or in a
canopy that has a small heater in its roof, in order to
replicate rising temperature. These experiments have determined
that flowering and leafing occur between 1.9 and 3.3 days
earlier for every one degree Celsius (1.8 degrees Fahrenheit) in
temperature increase. But the study says the true figure is far
higher. Plants start to grow leaves and flowers between 2.5 and
five days earlier per one degree C (1.8 F), it says. It bases
this on a comparison between warming experiments on 1,634 plant
species and long-term observati