The warm winter of 2014-15 is a dress rehearsal for 2050, a University of Washington climate scientist told utilities and conservationists in Seattle.
Electric utilities in the Pacific Northwest depend heavily on hydroelectric power. Predictions of a warmer, wetter century for this region may seem harmless, but they conceal some nasty realities.
The 2015 Northwest Clean and Affordable Energy Conference in Seattle opened with an excellent discussion of those realities, then moved on to examine how a shift to clean energy in all sectors (including transportation) will impact the region and its electric utilities.
“Science and strong data should be the basis for our policy decisions,” said NWEC Executive Director Nancy Hirsh in her opening remarks. The conference was well timed during the COP21 climate accord talks in Paris, and in the midst of Washington state’s preparations to comply with both the Clean Power Plan and a state mandate to limit greenhouse gas emissions.
Climate scientist Joe Casola is the Deputy Director of the Climate Impacts Group at the University of Washington. He began his morning keynote address by saying that the normal fluctuations between wet and dry years here are larger than the marginal changes expected in the climate by mid century. That was the good news. The remaining 43 minutes were not such good news.
The reason the predictions for 2050 fit within today’s “annual wiggles” is that the flywheel of global warming will drive about a 4° F temperature rise regardless of major mitigations even beyond what is likely to come out of Paris this week. Last water year’s wiggle was 4° F. (The water year is from October through September. Mr. Casola noted that Earth’s atmosphere experienced about a 1° F change in the entire 20th century.)
It is beyond the middle of the century when today’s actions yield significant improvements in the model: a change of about 5° F, versus 10° F for business as usual.
“Warmer and wetter” is indeed the prediction for this region over the next few decades. How could warmer be a bad thing in the cold and drizzly Northwest? And will these rain-drenched people really notice a little more precipitation?
“Annual total precipitation upticks a few percent,” says Mr. Casola of the 2050 model, “and that’s smaller than the swings we already see.”
The big difference in precipitation, he says, will be increases in the heaviest rainfall. A warmer atmosphere carries more moisture, so when heavy rainfalls come we can expect them to be more severe.
“That will impact the landscape as a whole, from forest and ecosystems to our built infrastructure and energy infrastructure,” Mr. Casola says. Dam operators can expect changes in sediment loads, and communities can expect more flooding. All of that costs money.
And it will indeed get warmer as 2050 approaches, which will grow market demand for energy during air-conditioning season by 20 to 30 percent, while energy demand during heating season declines by 30 to 40 percent.
“That doesn’t look all that different from the year we just had,” Mr. Casola says. “It was 4° F warmer than we’re used to, just like the prediction for 2050.”
“Snow is the headline story,” he says. Even with slight increases in precipitation, there will still be a significant loss of snow. That’s not good news for hydropower, which relies on energy storage in the form of reservoirs. Without runoff from snow melt, those reservoirs shrink and power turbines stand still. Unfortunately that happens in a season when demand for energy will be on the increase.
“Northwest snow takes a big hit. The total loss by mid century is 20 to 30 percent – and higher in Washington,” Mr. Casola says.
Some rivers will be affected more than others. Those watersheds supplied mostly by rainfall will be the least affected. Those supplied mostly by snowmelt will be significantly affected late in the water year, until about 2080 when snowfall is gone. “That can only exacerbate existing competition for those water sources at that time of the year,” Mr. Casola says.
Management will be the key to adjusting for these changes. “The risks and solutions are shared. If you optimize for hydroelectric dams, that affects agriculture and salmon.” Mr. Casola urged the parties to pursue their management solutions together. “If all communities try to manage this on their own, we will just have another set of tough water challenges.”
While the most recent winter was an anomaly, it was what Mr. Casola calls “a dress rehearsal for mid century.” He considers that a tremendous opportunity: “What worked and what didn’t? Can we learn lessons and broaden them into a wider strategy?”
Mr. Casola says that you have to look back as far as the 1930s to find a water year as warm as 2014-2015. “But that’s not a one-time thing. It’s a sneak preview of future conditions,” he said to the audience of utility executives and conservation activists. “Are you ready for an extended version of that?”
The Northwest Energy Coalition hosted the conference. NWEC is an alliance of about 100 organizations, including utilities, in the Northwest and British Columbia. The nonprofit diligently promotes sustainable energy, consumer protection and habitat restoration, as it has done since 1980s.
Photos courtesy NWEC/JJ McCoy, used by permission.
Corrections have been made in this article. The previous water year was remarkably warm, not dry. The temperatures stated were F, not C.
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