Wednesday, February 1, 2012

Shouldn't snakes still be hibernating?

This little fella was out and about at Cayuga Nature Center on January 31, 2012!

Upstate New York snakes tend to hide away in winter, but when temperatures warm, they'll come out and sun themselves. And this week has been warm over a broad swath of the country, hitting 56° in Ithaca, tying the record high for the date set in 1956. 

Snakes usually stay hidden away until around March. Is this global warming? Or, as a Facebook comment suggests, "Global weirding?" 

All we can say is an indecisive maybe. Ok, that's not all we can say, or there wouldn't be a blog post about it, would there? But the maybe has to come first -- these warm days are weather, not climate, and it's really hard to tie an individual case of unusual weather to climate change. 

But what the scientific consensus says about climate change indicates we should expect to see snakes coming out earlier than we used to. And other changes that mark the coming of spring will typically come earlier too. 

Another commentator noted that some trees are already budding. That's not unusual, quite a few trees normally form buds before winter sets in, as another commentator (my brother-in-law) noted. Those buds get bigger and more noticeable when it warms though, and again, that's tending to happen earlier. 

Last week, the United States Department of Agriculture, released an updated Plant Hardiness Zone Map. Check out the interactive map here, where you can click on the map or type in your zip code to find your zone. The Washington Post made a different interactive map of the information -- comparing the 2012 map to the 1990 map it replaces.

Again, things are complicated so not all of the changes here can be attributed to global warming, but the northward shift of hardiness zones is what climate models predict and it's what happened. And, the weirding idea is also evident here -- in some places zones shifted southward, but that's less common as you look across the map.

Something a bit simpler to indicate that we can expect to see more snakes in January is the trend shown clearly in the graph below.
From Joe Romm's post here.

The graph shows that the 1980s were the warmest decade on record until the 1990s came along and were warmer. The 1990s held the record until the first decade of the new century took its place. So, we can't say that snake was out on January 31 because of climate change. But we can say there's a reasonable chance and that there's a good chance of seeing more snakes in the coming Januarys.

Don Duggan-Haas

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