Cold and Hot

It seems that winter has finally ended for us.  It was an exceptionally cold, record-breaking winter.

That seems strange, given that seemingly the rest of the country continues to experience record heat. I came across this explanation:

the winter of 2014/2015 was characterized by an unusual pattern of atmospheric circulation, with the jet stream lying well north of its usual location over Eurasia and the North Pacific, and then plunging southwards over eastern North America. This pattern was associated with unusually warm conditions extending across northern Eurasia, the Bering Sea and Sea of Okhotsk, Alaska and into the western part of the United States, contrasting with cold and snowy conditions over the eastern half of the United States.

So the culprit seems to have been “an unusual pattern of atmospheric circulation.”

Here in the east that meant a cold winter.  But what about elsewhere?

For one thing, the March level of Arctic sea ice was the lowest ever recorded, 23,000 square miles less than the previous record.  Of course while this year’s “unusual pattern of atmospheric circulation” may have accelerated the decline, it didn’t begin it.  March sea ice has been dropping by a rate of 2.6% per decade  since the measurements began.

sea ice

Arctic sea ice levels for 2015 are clocking in at more than 2 standard deviations below the 1981-2010 average.

arctic sea ice

But decreases in sea ice aren’t the worst of it (for more about the sea ice effect, visit HERE).

Perhaps the effect that holds the most potential for short-term disaster is the heat and drought in California.

This year’s hot weather has exacerbated a situation there that was already critical. Consider this from Bloomberg Business:

The California heat of the past 12 months is like nothing ever seen in records going back to 1895. The 12 months before that were similarly without precedent. And the 12 months before that? A freakishly hot year, too.

What’s happening in California right now is shattering modern temperature measurements—as well as tree-ring records that stretch back more than 1,000 years. It’s no longer just a record-hot month or a record-hot year that California faces. It’s a stack of broken records leading to the worst drought that’s ever beset the Golden State.

The chart below shows average temperatures for the 12 months through March 31, for each year going back to 1895. The orange line shows the trend rising roughly 0.2 degrees Fahrenheit per decade, just a bit faster than the warming trend seen worldwide.

california heat

The last 12 months were a full 4.5 degrees Fahrenheit (2.5 Celsius) above the 20th-century average. Doesn’t sound like much? When measuring average temperatures, day and night, over extended periods of time, it’s extraordinary. On a planetary scale, just 2.2 degrees Fahrenheit is what separates the hottest year ever recorded (2014) from the coldest (1911).

California has seen droughts before with less rainfall, but it’s the heat that sets this one apart. Higher temperatures increase evaporation from the soil and help deplete reservoirs and groundwater. The reservoirs are already almost half empty this year, and gone is the snowpack that would normally replenish lakes and farmlands well into June.

If that’s not sufficiently sobering, consider the conclusion:

That’s part of what makes this drought so troubling. The 4.5 degree above-normal temps that California has seen are unprecedented, but not entirely unexpected. The International Panel on Climate Change, which includes more than 1,300 scientists, forecasts global temperatures to rise anywhere from 2.5 to 10 degrees Fahrenheit over the next century, depending largely on how quickly humans reduce our dependence on fossil fuels.

That means the conditions that are wreaking so much havoc in California today fall well within the range of what may be considered “normal” in the not-too-distant future. The impact of such warming is expected to vary dramatically by region. The scientists’ forecast for the U.S. Southwest: increased heat and drought—and decreased water supplies and agricultural yields.

We aren’t nearing the end of California’s climate troubles. We’re nearing the beginning.

The bottom line seems to be that while we probably shouldn’t expect repeats of this year’s east coast cold, maybe we’d better get used to conditions like the west coast heat.

We may well come to regret becoming so dependent upon California agriculture.

Go check out the rest of the Bloomberg piece HERE.  The California drought maps are especially important.  That dark brown area supplies much of the country’s (and the world’s) produce.