Climate patterns show that year after year, springtime is getting warmer and starting earlier in the year to varying degrees in different regions of the country and the world. But it poses major risks everywhere.
THERESA CRIMMINS: By and large, there is a pattern that-- that springtime is generally warmer earlier in the year than it used to be in previous decades. How much that the increase in warmth has occurred is variable from-- from region to region.
So the southwestern US is actually the part of the country where we see the strongest trends towards earlier warmth and greater warmth than we have in the past. It's not as prevalent in the Southeast. That part of the country-- it's actually been described that they have more of a warming hole. Urban areas tend to experience the heat to a greater degree than less-developed, more rural parts of the country.
We've seen a lot of different kinds of consequences as a function of warmer springs and earlier springs. Insects that can be vectors of disease may not have their populations knocked back to the same degree in the-- as in the past, leading to more disease. We are also seeing an earlier start to the pollen season, and consequently, much worse allergies and even visits to the emergency room as a consequence of uncontrolled asthma because of this earlier start to the pollen season and longer duration and intensity to that. And in some recent years, we've had huge impacts to fruit crops as a consequence of those-- the early, early warmth, followed by freezing temperatures.
For example, a lot of fruit trees, like apples and cherries, put on their flower buds before their leaf buds and if those flower beds are hit by frost, then there's no fruit that can develop. We also see consequences where species that depend on each other to be active at the same time are not responding to the increasing warmth to the same degree, and so then we're starting to see what are called biological mismatches, where, say, plants that require a particular pollinator to be present are not experiencing-- or responding to the warmth in the same way.
Things like tulip-time festivals, or lilac festivals, or even cherry-blossom festivals can be impacted when the dates are set far in advance and the biological event is very responsive to the weather conditions in a given year. We've seen that in a couple of recent years, where, with really early warmth, the cherry-blossom festival in the tidal basin in DC hasn't really coinci-- coincided with the actual flowering of all those iconic trees.