California and the Southwest will be hit by drought and wildfire. The East Coast and Southeast will suffer appalling heat waves, hurricanes, and rising sea levels.
Policy makers and city planners are calculating when the future climate will depart from its normal variability. How much time do we have to act? A decade? A century?
“If you do not like it hot and do not want to be hit by a hurricane, the options of where to go are very limited,” said Camilo Mora, a geography professor at the University of Hawaii and lead author of the paper in Nature predicting that unprecedented high temperatures will become the norm worldwide by 2047.
“The best place really is Alaska,” he added. “Alaska is going to be the next Florida by the end of the century.”
Mora et al used the complete set of available climate models to calculate the year when the Earth’s climate will move beyond what we have experienced in our recent past. In other words, in what year will the climate become more extreme than the year of the most extreme events we have witnessed in the last 150 years?
They looked at seven different climate variables, including temperature, precipitation, and ocean acidity. According to their results, the climate of the Earth will depart from its normal variability about 35 years from now (in approximately 2050) under business as usual human activity. On the other hand, if we take seriously the threat of climate action, we can push that date by some 20 years.
But this global average threshold is only part of the story. The authors recognized that climate change will occur more rapidly near the poles (for instance, temperature changes will be greater near the poles than in the tropics). However, the present climate in the polar regions is already more variable, and biologic systems and humans living there are more adapted to climatic shifts.
In contrast, in the tropics, given their more stable climate, it is easy for even small changes to surpass historical extreme records. In other words, the tropics will face unprecedented climates sooner. The problem is that these small climate changes pose serious challenges for people and species that are not equipped to adapt.
What this means is the authors find a “double jeopardy” situation. Humans, plants, and animals will live in the tropics and will be more susceptible to small changes, or they may reside in higher latitudes and experience the largest climatic shifts.
The study shows that the earliest expected occurrences of unprecedented climate change will occur in the tropics. That zone, with its richness in biodiversity, will see climate shifts a decade earlier than elsewhere. This is particularly true of coral reefs, which will see shifts about 20 years earlier than average. In the case of ocean pH, this variable moved into unprecedented states in 2008.
Under any model of climate change, scientists say, most of the country will look and feel drastically different in 2050, 2100 and beyond, even as cities and states try to adapt and plan ahead. The northern Great Plains states may well be pleasant (if muggy) for future generations, as may many neighboring states. Although few people today are moving long distances to strategize for climate change, some are at least pondering the question of where they would go.
“The answer is the Pacific Northwest, and probably especially west of the Cascades,” said Ben Strauss, vice president for climate impacts and director of the program on sea level rise at Climate Central, a research collaboration of scientists and journalists. “Actually, the strip of coastal land running from Canada down to the Bay Area is probably the best,” he added. “You see a lot less extreme heat; it’s the one place in the West where there’s no real expectation of major water stress, and while sea level will rise there as everywhere, the land rises steeply out of the ocean, so it’s a relatively small factor.”
Clifford E. Mass, a professor of atmospheric science at the University of Washington, writes a popular weather blog in which he predicts that the Pacific Northwest will be “a potential climate refuge” as global warming progresses. A Seattle resident, he foresees that “climate change migrants” will start heading to his city and to Portland, Ore., and surrounding areas.
“The Pacific Ocean is like our natural air conditioning,” Professor Mass said in a telephone interview. “We don’t get humidity like the East Coast does.”
As for the water supply? “Water is important, and we will have it,” Professor Mass declared. “All in all, it’s a pretty benign situation for us — in fact, warming up just a little bit might be a little bit welcome around here.”
Already, he said, Washington State is gearing up to become the next Napa Valley as California’s wine country heats up and dries out.
There may be other refuges to the east. Don’t count out the elevated inland cities in the country’s midsection, like Minneapolis, Salt Lake City, Milwaukee and Detroit, said Matthew E. Kahn, a professor of environmental economics at the University of California, Los Angeles.
“I predict we’re going to have millions of people moving to those areas,” he said in a telephone interview.
In his 2010 book “Climatopolis,” Professor Kahn predicts that when things get bad enough in any given location — not just the temperatures and extreme weather, but also the cost of insurance and so forth — people will become “environmental refugees,” fleeing cities like Phoenix, Los Angeles and San Diego. By 2100, he writes, Detroit will be one of the nation’s most desirable cities.
What can we do about this? It is commonly thought that increasing the natural habitats of species will be a significant help for this problem, but the authors came to a different conclusion. They point out that since the protected areas will undergo similar climatic shifts, they won’t be of much use to suffering species. Also, since many of the tropical hotspot areas are located in low-income countries, the ability to fund adaptive strategies will be limited.
Finally, and perhaps most interestingly, the authors isolated key biological groups in order to compare the time they reach climatic thresholds to the average globe. Some of the biggest losers – coral reefs (already mentioned), mangroves, seagrasses, marine reptiles, cephalopods, and marine fish – will experience far earlier climate disruption than the rest of us. That should give no consolation; in a world as interconnected as ours, we will all feel these climate shifts sooner rather than later.
As for people, some 5 billion people, mostly in developing countries, could be facing unprecedented climates by 2050.