EXTREME IS OUR NEW NORMAL IN THE ERA OF GLOBAL CHANGE
Here in the wintry Northeast, cities are shattering records for the snowiest and coldest ever. Boston called out the National Guard last month to shovel out the T, and the National Weather Service office in Taunton, MA reported on Sunday that February was the all-time snowiest February ever in Boston since 1872, with a record 64.8 inches, burying the record set at 41.6 inches in 2003. Boston also beat its all-time record of any snowiest month of 43.3 inches set in January 2005. Seasonal snowfall was also a record, at 99.4 inches, beating 81.5 inches set in the winter of 1993-1994. February was also the second coldest, with a monthly average of just 19 degrees. So it goes all over the Northeast, where this winter temperatures have been tumbling to record lows and snow has been piling up to record highs. Transit workers are bashing ice out of the tunnels in New York and here at the Harvard Forest, in Central Massachusetts, I don’t know why they ever put the snow blower away.
There’s three feet or so of snow out my window here and more on the way. I went out for a snowshoe this morning to enjoy the animal tracks on fresh snow that fell overnight. The first day of spring is March 20, but it sure seems a long way away.
Meanwhile, my home town of Seattle is the mirror image of Boston in more than the Superbowl. While we are piling up snow records here, Seattle has just recorded a record warm winter. There is so little snow, the ski resorts have choked and there’s serious concern about winter snowpack — our source of surface water and nearly 90 percent of the power supply for Seattle City Light. Good luck with that this year: my husband Doug all last month was emailing me photos of daffodils, crocus, and daphne in bloom weeks ahead of schedule. The star magnolia is in full glory, and the evergreen clematis, too. On Sunday, he cut the grass. Really!
My friend Jonathan Martin on the Seattle Times editorial board wrote an ode to winter published today, pleading the snow gods to return.
Things could still change, he rightly points out. I still remember the press conference in which then Gov. Gary Locke declared the state to be in a drought in March, 2001. A deluge of snow and rain in the lowlands arrived within days, and the water year ended up just about average.
Climate change deniers will surely seize on the ice box of this winter in the Northeast. But the true, long term story of our warming climate is beyond dispute.
Last year was the hottest on Earth since record keeping began in 1880, surpassing 2010 as the previously warmest year. The ten warmest years ever have all occurred since 1997, if you are counting.
Maybe if as scientists do we all called what we are witnessing “global change” rather than “global warming,” this would all make more sense, or at least be less of a predictable laugh line. Because it is change that we are living. Not warming everywhere…but change. At a rate that is smoking hot.
Aaron Ellison, a senior ecologist at the Harvard Forest, points out the sorts of extremes we are experiencing is exactly what we should be expecting. “Every day, it’s another anomaly,” he says. “This is what systems do, when they reach a tipping point.”
A wholesale reset is nothing new for our Earth, whose climate is not terribly stable. Twenty thousand years ago, Seattle, Boston and New York were under a mile of ice. In just the last 12,000 years, sea levels have risen 400 feet, with the melting of all that ice. That’s a blink of an eye, geologically speaking. Go back 650 to 750 million years, and there’s evidence Earth was a giant snowball, one big ball of ice. And earlier, as dinosaurs walked the Earth, our planet was ice free, all the way to the poles. Since modern humans arrived, about 200,000 years ago, we’ve lived in a relatively stable, friendly climate between reigns of ice, the most recent ice age ending 12,000 to 15,000 years ago. Because it’s what we know, we think this climate that we are used to is what life on Earth looks like. But it wasn’t, much of the time, looking into the past, and surely, at the rate we are going, it won’t be in the future.
Human-caused climate change is not controversial among climate scientists; it is a predictable fact, and really, a matter of simple math. Svante Arrhenius, the Swedish physicist (1859-1927) discovered the greenhouse effect, and understood that if we doubled CO2 in the atmosphere, it would increase surface temperatures by 4 degrees, and if we increased it fourfold, the temperature would rise by 8 degrees. That was in 1906. Notes Kerry Emanuel, the climate expert at MIT, “With a piece of paper and a pencil he gets to nearly the same place as the Intergovernmental Panel on Climate Change in its 2013 estimates.” Impressive, true, but not really surprising for a guy good at figures. Global warming is, after all, at its simplest, a matter of adding more carbon into the atmosphere than the standing stock of plants in the living biosphere, both on land, and in the planet’s waters, can absorb.
It’s not the absolute number of parts per million of C02 in the atmosphere that matters; it varies from season to season, and year to year anyway. It is the rate of change over time that counts. The amount of C02 in the atmosphere today is higher than it has been in the last 800,000 years, and probably higher than it has been in the past 20 million years. Think of it this way: We have caused the CO2 content in the atmosphere to rise as much since the big oak sprouted as it rose over 8,000 years during the transition from the last ice age to the current interglacial period. Such a fast rate of change in the chemistry of the atmosphere is probably without precedent in Earth’s recent history, putting us in what geologists call a no-analog world. And we have a lot more fossil fuel left to burn, if we choose to. Work at it, and we could stoke temperatures right back to the dinosaur days of the Cretaceous.
Global warming, climate change, these are useless terms really, that fail to communicate what is really happening: The problem isn’t just that we have warmed the atmosphere. It is that we have created an entirely new system, with feedbacks of its own. The temperature of the air, the winds, the mixing of ocean currents, and chemistry of the seas, food chains, the migrations and interactions of plants and animals and their home ranges — they are all connected. Change any part as fast as we have, and all the rest will cascade into new interactions that are already changing things for us, and many other beings with whom we share the planet. Meanwhile C02 levels will go beyond doubling and by the end of the century, most experts think, and probably triple.
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