What happened to global warming?

In the Boston area where I live we are getting pounded with snow leading to record accumulations and the inevitable quips ‘Whatever happened to global warming?’  I have been pondering my response to this for the last days when this morning my acquaintance Carolyn Johnson, science editor of the Boston Globe, has an excellent piece in the paper giving a detailed answer entitled ‘How warming can worsen snowfalls’. 

First, it is more helpful to use the term Climate Change rather than Global Warming, even though it is true that the basic thing that is happening to our planet is a warming due to substantially higher levels of CO2. As a result, the entire planet has warmed up 0.74*C ( 1.33 F) between 1906 – 2005. That doesn’t sound much. Tell most people and they just shrug and say ‘Huh, I’ll just wear a lighter shirt in summer and turn on the A/C more often.'

But think about that for a moment; 93% of that extra heat has been absorbed by the oceans. Think of the amount of extra energy it has taken to heat up the entire Atlantic and Pacific etc oceans. That energy is going to be expressed in various ways: stronger hurricanes and more energy in the jet stream, as well stirring a more aggressive arctic vortex in the winter. 

I first ran into this when researching the paper that I co-authored in 2012 with my colleagues Walter Kittredge, Elizabeth Wright and Donald Lubin entitled Changes in the vascular flora of the Middlesex Fells Reservation, Middlesex County, Massachusetts, from 1895 to 2011. Rhodora, Vol. 114, No. 959.  In our study of the plants of this forest reservation, four miles in from the sea, we did find that some cold-loving plants had disappeared and a few other species had come in from the south. But we found a more marked change in those that liked things wetter; for example a 10% increase in wetland species. When I studied weather reports for Boston I found that there had been an 8% increase in precipitation in the last hundred years, most of that increase in the last thirty years. ‘Precipitation’ includes both rain and snow, the latter being measured in special receptacles that melt the snow and then record the water content. If it’s fluffy snow, ten inches equals just one inch of rain. 

In the warmer months Rhode Island, Eastern Massachusetts and SE Maine get more rain because the prevailing winds from the south and south west are carrying more moisture.  An Atlantic ocean current comes south down the coast of New England carrying an increased quantity of cold water (along with damp cool air) because of the melting arctic ice cap. And these air masses tend to collide around the coast of Massachusetts. In the winter a more energetic jet stream also drags more arctic air our way.  All this adds up to heavier snow storms in the winter and more rain the rest of the year. But, because of global warming our winters (though intense) are going to get shorter. The local records being beaten this week in Boston are for amounts of snow in a limited period – a week or two weeks; but even this winter is unlikely to beat the winter-long record set back in the winter of 1995-96 when Boston got 107.6 inches (2.73 meters) of snow. 

So, I guess I’ll have to go and do some shoveling. But I’m encouraged by the belief that Spring is not that far away. 

And while we Bostonians complain about all the snow, climate change is having, and will have, far more serious consequences in other parts of the world such as Southern California, the Philippines, East Africa and certain Pacific island nations.