Ice and snow

Very cold! On Wednesday night my thermometer read -21C - a low temperature reasonably common here 20 years ago, but rarely experienced since then. My first experience of it being rapidly painful to be outdoors. A large mass of really cold arctic air moved down from Canada, picking up moisture from the unusually warm Great Lakes, and depositing it as snow. In fact, so hungry for moisture was this dry cold air it picked up enough from the cooling ponds of a nuclear power station in New York State to drop it as an inch of snow in a dramatic downwind plume - as this radar image shows:

There's some rather beautiful ice patterns building up on my windows too:

I spent Thursday in Boston, working in the grand Widener Library, and visiting the Harvard Center for Health and the Global Environment, which is working to raise the awareness of the effects of global changes on human health, particularly of climate change and habitat loss. 

Harvard Yard, Boston. It's -15C!

In the cathedral hush of the Widener Library

Coincidentally, the following day I read an astounding piece of research with results I'm not sure even the authors entirely believed . Ash trees across the Midwest and Canada have been dying, killed by an insect, the Emerald Shoot borer. In many places this has had a really dramatic effect on woodland and urban trees - Ottawa for example has lost about a third of all its urban trees. Now, there's evidence that human health benefits from being in, or near, or even just within view of natural environments, including some work showing that patients recover more quickly from surgery, and need less pain medication simply by being able to see trees from their hospital ward. Quite how this works isn't clear, and may have a range of mechanisms - reduction of pollution, shade and psychological effects have all been mentioned. Anyway, these researchers decided to compare the mortality from heart and lung diseases before and after the removal of ash trees by the Emerald shoot borer. Across the 15 affected states, they found that after allowing for every other change or effect they could think of, the residual effect of the loss of ash trees was correlated with 21000 additional deaths between 2002 and 2007. In the same period, murders using guns in the US was about 50000 - making this little insect a mass killer of humans as well as trees.

As well as being a fascinating piece of research, this is a good example of how science unravels the truth about the world we live in. Other researchers will look at this, check the working, and think about ways to prove or disprove the connection - and to try and understand the causal connection to find out what is really going on. It'll be interesting to follow that discussion. To read the full paper, go to:

http://socialcapitalreview.org/wp-content/uploads/2013/01/donovan_et_al_media_copy.pdf