A Canary in the Coal Mine
The Arctic seems to be getting warmer. So what?
A. “Climate change in the Arctic is a reality now!” So insists Robert Corell， an oceanographer with the American Meteorological Society. Wild-eyed proclamations are all too common when it comes to global warming， but in this case his assertion seems well founded.
B. At first sight， the ACIA’s （American Construction Inspectors Association） report’s conclusions are not so surprising. After all， scientists have long suspected that several factors lead to greater temperature swings at the poles than elsewhere on the planet. One is albedo — the posh scientific name for how much sunlight is absorbed by a planet’s surface， and how much is reflected. Most of the Polar Regions are covered in snow and ice， which are much more reflective than soil or ocean. If that snow melts， the exposure of dark earth （which absorbs heat） acts as a feedback loop that accelerates warming. A second factor that makes the poles special is that the atmosphere is thinner there than at the equator， and so less energy is required to warm it up. A third factor is that less solar energy is lost in evaporation at the frigid poles than in the steamy tropics.
C. And yet the language of this week’s report is still eye-catching： “the Arctic is now experiencing some of the most rapid and severe climate change on Earth.” The last authoritative assessment of the topic was done by the UN’s Intergovernmental Panel on Climate Change （IPCC） in 2001. That report made headlines by predicting a rise in sea level of between 10cm （four inches） and 90cm， and a temperature rise of between 1.4°C and 5.8°C over this century. However， its authors did not feel confident in predicting either rapid polar warming or the speedy demise of the Greenland ice sheet. Pointing to evidence gathered since the IPCC report， this week’s report suggests trouble lies ahead.
D. The ACIA reckons that in recent deca