Squirrels and climate change

Winter is a pain in the animal kingdom. Birds can flee it by migrating to warmer climes but grounded beasts, including mammals, have no choice but to stick around. To cope, many species have learned to hibernate. Some, like the Columbian ground squirrel, spend up to nine months of each year in their alcoves. This conserves energy but leaves them with only three months to plump up for the next winter and, crucially, to procreate.

To make matters worse, climate change is leading them to emerge from hibernation later than usual. On the face of it, global warming should mean that the critters have longer ice-free periods in which to go about their evolutionary tasks. But it can also disturb weather patterns, which may have the opposite effect. Jeffrey Lane, an evolutionary biologist at the University of Edinburgh, in Britain, points out that in the squirrels’ natural habitat of the Canadian Rockies, climate change manifests itself in late-spring snow storms.

Because female Columbian ground squirrels remain in their place of birth, the researchers were able to tag and observe them and their offspring each year for the past two decades. A typical female would bear three kittens. On average, only 30% of them survive the first winter, enough to sustain population numbers since female squirrels can expect three or four litters in their lifetime. If the proportion falls, however, the population dwindles.

As Dr Lane and his colleagues report in Nature, in the first decade of the study the number of squirrels dropped just once. But it fell in four of the past ten years. Dr Lane speculates that this might be explained by the fact that over the past 20 years the late snow has delayed the melting of ice by half a day each year, on average, shortening the squirrels’ breeding and feeding season by several days and disrupting their life cycles. Since mothers have less time to squirrel away (if you will) nutrients in their bodies before it is time to hibernate, the suckling kittens are left more vulnerable.

Correlation is not causation, of course, and other factors might be behind the decline in the number of squirrels. But longer winters are unlikely to help.

Also published on economist.com.


  1. Lane et al.Nature, 2012.
  2. Lane et al.J. Evol. Biol., 2011, 1949.

 Image credit: Jeffrey Lane.

What difference do I make?

The poorest half of the world produces 7% of global carbon emissions. The richest 7% produces half the carbon emissions. – The Economist

An article in the Economist that argued that attempts at curbing population growth isn’t an answer to scarce resources caught my attention because of the two sentences above.

Even without looking at the figures that have been quoted to define the ‘poorest half’ or the ‘richest 7%’, I can safely assume, given that I am a poor graduate student in the UK, that I fall under neither of two categories of the world population. What does that say about my carbon emissions? Not much.

But I know that working in a synthetic chemistry lab that is air-conditioned, living in a house that has central heating and flying back home to India once a year probably means that my carbon emissions lie on the higher end of the spectrum. I do not take pride in this, but the choices that I made with the best intentions for my career have put me in this situation. I am well aware of my situation and I try my best to do something about it:

  • I chose to become a pescetarian.
  • I campaigned for a meatless day a week.
  • I don’t shy away from asking difficult questions.
  • I ensure lights are off when they are not needed.
  • I turn off taps if the water isn’t being used.
  • I turn off the heater in my room when I’m not there.
  • I use a bicycle to go anywhere <10 miles.

I do this despite all the wasteful habits that people around me have. I have housemates who have no qualms leaving lights turned on. I have lab-mates who never think twice before mixing chlorinated waste with non-chlorinated waste. I have friends who won’t mind having a hot water bath everyday. I watch students in college halls everyday pile up food in their plates and then throw heaps of it in the bins because they’re ‘so full’. Every time I watch this happening, a little bunny dies inside me.

If I start calculating how much emissions I cut by following the things I listed above, the number will probably be small. Small enough to make me wonder, especially looking at those around me, what difference do I make?

But then I think that I do what I do not just for the absolute contribution that I make to cut emissions, but also because I care about the environment. I believe that it is important to be as morally responsible to your future generations as possible. I know that beliefs that I build today are going to affect my decisions to tomorrow. These decisions may well have large consequences then.

I’ve had a discussion about these little things that I do with many people. Some of them have wondered whether the effort I put in to doing them is worth the impact they make. Of course I believe the effort is worth it, especially if you take into account the effect of one’s belief systems. But actually, the effort put into doing them is much smaller than most people imagine it to be. Most of the little things I do have become a habit. I don’t have to consciously think that I should turn off the lights or turn off the heater, I just do it.

The other argument that I’ve come across is this: the fact that I do little things I give myself the pleasure of believing that I make some difference. In effect, I am more liable to not worry about the larger problem because in my own little world I am doing plenty. Actually, this argument has got the logic all wrong. If I do the little things, I am only more likely to do bigger things (like giving up meat or campaigning). As I said before, doing these little things has become a habit for me and I don’t derive ‘pleasure believing that I make some difference’ every time I turn off the light in an unoccupied room. So it’s definitely not offsetting me from the larger goal.

What difference do I make? May be very little today but over a life time plenty.