The New Normal Weather

The New Normal Weather

Last weekend I fled town to hit the slopes. We rented a chalet on the side of the hill, and hearing reports of great snow I excitedly waxed and sharpened my skis in preparation. But then the night before our weekend getaway, the snow melted. The patches of white on the hills were matched by exposed mud and grass.

As we sat on the deck looking over the snowless hills and sipping beers instead of skiing, the conversation inevitably turned to climate change. We all wistfully talked about the good old days, when winter was, well winter.

A report released by the U.S. Global Change Research Program earlier this week, spelled out the new reality we can expect when it comes to weather in the coming decades. In short weird and warm weather looks here to stay, and severe droughts and floods are the new normal. Say goodbye to permafrost and welcome to ticks. That said, the scenario is not entirely out of our control – the report maps out the worst- and best-case scenarios dependent upon greenhouse gas emissions (SRES A2 marks the worst case and SRES B the best case).

Here are some of the sobering and worrisome highlights (... or, perhaps more appropriately, lowlights) from the report.

No surprise that temperatures are predicted to rise. Worrisome though is just how much. In the worse case scenario the average expected increase is over 11 degrees.

 Temperature Projections

In contrast, under the best case scenario, we’re looking at a 6 degree increase over the next century.

Temperature Change Projections

To put all that red in the worse case scenario in perspective, the number of days over 100 degrees will spike in the south and the plains, quite literally off the charts.

Days Over 100 Degrees

Nowhere are these shifts more obvious than in the land of ice and snow to the north. Alaska’s warming will continue at an alarming rate.

Alaska Will Continue to Warm Rapidly

As a consequence, thawing of permafrost is expected to continue at an alarming rate, which will further contribute to warming through its release of methane into the atmosphere. For those communities in the north, this warming will put extreme pressure on infrastructure, water supplies, sanitation systems and ice roads, threatening traditional ways of life.

Thawing Permafrost in Alaska

And the sweaty story continues in the south. Remember the drought of last summer? We’ll be seeing it again. Under a high emissions scenario the southwest will see far less rain and increased severity of droughts.

Extreme Droughts in the US and Mexico

And less rain means significant reductions in water resources available throughout the country.

Projected Changes in Water Withdrawal

However, don’t write precipitation off as a thing of the past... it will just become more a thing of the north. Heavy precipitation and severe storms are expected to increase in the northeast. The graph below shows the results of these contrasting trends on expected flood levels.

Trends in Flood Magnitude

The report goes on to outline more consequences of the warming effects. In short expect ticks to take over more of the country, increased levels of pollen to agitate your allergies, and forest fires to become more frequent and severe. Sea levels will continue to rise in ways and coastal cities, power plants and airports will all be vulnerable to flooding.

The situation sounds bleak, I know. The report though is not entirely doom and gloom. The best case scenarios are still very much achievable, though not without a drastic change in behavior. Specifically, that would require that we limit global greenhouse gas emissions to a peak of around 44 billion tons of carbon dioxide per year. To put that in perspective, 2011 global emissions were approximately 37 billion tons; levels have risen steadily by 0.9 billion tons per year for the past decade. Business as usual has us on track to surpass 44 billion tons in less than a decade. Clearly achieving a change of this magnitude will require an international commitment to collectively changing the path we’re on.

Is that possible? It’s hard to say, but I think we sure as hell should try.

January 16, 2013