Some recent coverage has muddied this point, so let's help with the clean-up.
Freakish warmth: t-shirts first, questions later
People are golfing and mowing lawns in Wisconsin. They're gawking at cherry blossoms in Philly and D.C. My family recently played touch football in t-shirts on a field dotted with dandelions.
Day after day, popular outdoor spots in Northeast cities are transformed into a sea of naked arms, hatless heads, and the occasional bare chest, even as Christmas festoonery blinks incongruously nearby.
Santa, in an enigmatic move, was spotted water skiing in ice-free, snow-free, cold-free Buffalo, NY, and Coon Rapids, MN. My kids are saying things like "it's practically CHRISTMAS!!" and "What the HECK??" And no one in my house has touched a mitten in weeks.
A friend and I recently traded notes about the previous night when she had narrowly avoided the squashing of a non-hibernating frog, and I had squashed a non-waiting-for-spring-to-be-born mosquito.
The nightly news is covering black bears in New England who have put off hibernation to molest bird feeders. Bulbs are sprouting like it's springtime, and my March-flowering quince is December-flowering. There are scattered reports of birds acting badly, like the half-dozen species of warblers, who should by now be as far South as Central America, observed lingering on in Maine and thus courting death. And there are reports of monarch butterflies as if they didn't have enough problems, emerging in December in several New England states briefly. Christmas is coming, the goose is getting fat, because migration is for suckers.
These things are due to the fact that it's freakishly warm out there.
Freakish warmth by the numbers
We've all experienced unusually warm spells. But these numbers help explain the unique nature of recent warmth.
- Warmest autumn: "Meteorological autumn," September through November, was the warmest for the lower 48 states since record-keeping began 121 years ago, and the warmest globally, in the 1880-2015 record, smashing the record set just the previous year.
- Hottest months: In recent months, records have also been set individually. The top three warmest months on record globally (measured by NOAA in monthly departures from the 20th-century average) are:
1) 0.99degC, Oct 2015 (the "greatest departure from average of any month in the 1,630 months of record-keeping.")
2) 0.97degC, Nov 2015
3) 0.91degC, Sep 2015
According to NOAA, "nine of the first eleven months in 2015 have been record warm for their respective months." And we have yet to count December, which is still steaming away. - Record-breaking days: In recent weeks, across the eastern half of the U.S., thousands of local records--nearly 6,000 as of December 18--have been broken, some by wide margins and some dating back to the 1800s. In terms of daily record highs, these records were broken just last weekend:
- Lexington, Kentucky, saw 70 degrees, breaking a record from 1873
- Joplin, Missouri, at 72 degrees, broke a record from 1907
- Cleveland shattered its 1949 record by a full 7 degree
- Washington, D.C., and Detroit both broke records held since the 1880s
- Dubuque, Iowa, broke its 95-year-old record by 5 degrees.
- Record-breaking nights: New York City set a daily record high at 64 degrees on December 12. Three days later, it set a new one at 68 degrees--at 2:03 a.m. Many other locations saw new daily high records set in the middle of the night. My weather app told me to expect 60 degrees at 3 a.m. the other night. In Massachusetts. In December.
- Wide margins: From the Plains, through the Midwest and South, to the Northeast, temperatures clocked in at 20 and 30 degrees above average--more like October days (wait, see previous bullets; scratch that)--and for days at a time.
- No snow in sight: Famously snowy Buffalo, NY, recorded no snow until last Friday--something it hasn't done since 1899. And there is little in sight for many states that are normally snowy in December.
- Warmth through the holidays: Weather forecasts for much of the eastern U.S. point to a very warm Christmas.
- What to expect in the new year? Accurately predicting what happens next this winter is very hard, given the big and only partially-understood dynamics. For more, watch for a forthcoming post from my climate-scientist colleague, Brenda Ekwurzel, who will outline the key indicators scientists will be watching this winter.
What's going on?
It's warm and snowless because of El Nino, the Arctic Oscillation, AND global warming.
Some recent coverage has muddied the connection and disseminated the idea (mainly through poorly worded headlines, unlike mine) that this heat is not the result of global warming. But of course, the vital underlying fact is that we've already created a good deal of warming (1 degree C, as of these past months), globally, and so the climate phenomena that play out on the world stage today--like this Oct-Nov El Nino, the third hottest since 1950; and this fall's warm Arctic, the highest land temperatures north of 60 degrees North since 1900--are inevitably playing out on top of, and being influenced by, these altered conditions.
The specifics of what's happening where El Nino, Arctic dynamics, and underlying warming meet are complex, and scientists are actively discussing how things might play out. However, the collective bottom line recognizes that global warming plays a role.
As the Guardian reported, NOAA's Deke Arndt puts it this way: "Long-term climate change is like climbing a flight of stairs: over time, you get higher and higher. El Nino is like standing on your tippy toes on one of those stairs. Together, both of those work to create the warmest temperature on record. We would not repeatedly threaten records if we had not climbed the stairs for decades."
Studies suggest that global warming will cause the formation of more extreme El Ninos. However, as the stairs analogy communicates, whether it's possible to blame climate change for this unusually strong El Nino or the ongoing behavior of the Arctic Oscillation doesn't diminish the role of climate change in our current experience.
2015 is the hottest year on record by a wide margin, topping 2014. 2014 became the hottest year, even in the absence of El Nino. We're climbing the stairs, picking up pace, and taking two at a time.
Whatever we want to call December's freakishly warm weather, whatever we're tempted to call the punishing cold and snow that could follow, we ought not to leave out the global warming propping it all up.
