Tim McDonnell joined Climate Desk after stints at Mother Jones and Sierra magazine. He remains a cheerful guy despite covering climate change all the time. Originally from Tucson, Tim loves tortillas and epic walks.
As climate change intensifies, one of the most surefire threats we're bound to face is increased flooding of coastal cities brought on by sea level rise. Taxpayers worldwide will be faced with more whopping bills—like the estimated $60 billion cost of Superstorm Sandy—to clean up damage in the wake of these events. But just how much money are we talking about here? According to a study out today in Nature, it's a freakishly large number: A dangerous combination of rising seas, sinking land, and growing coastal development could push global flood damages to well over $1 trillion every year by 2050.
Stephane Hallegatte, an economist at the World Bank, and his coauthors tallied up estimated flood damage losses for the world's 136 largest coastal cities, on the basis of local population and real estate and infrastructure values crunched with data on each location's elevation, exposure to extreme weather like hurricanes, and existing coastal protection infrastructure. Then he extrapolated these costs into the future using UN population and urbanization models, economic models from the Organization for Economic Cooperation and Development, and climate models of future sea level rise. The results were staggering: The $1 trillion figure, Hallegatte says, is just the bare minimum.
Without action to better protect these vulnerable metropolises, he says, "even in cities that are very well-protected today, losses will reach levels that are completely impossible to imagine." The map above shows the 20 cities with the highest estimated losses in the absence of any proactive measures.
Sounds grim, but there's a silver lining: Installing robust protective infrastructure that accounts not just for sea level rise but also population growth and future shoreline development could reduce annual losses to $52 billion. As is so often the case with climate change preparation, investment up front can save big bucks down the road. After all, Hallegatte says, even the cost of massive sea walls, natural barriers, and other coastal protection will seem like chump change compared to a scenario where "we have cities destroyed and we have to rebuild them again and again."
Climatologist Dorothy Peteet is combing through New York-area marshes for clues to future drought.
Piermont Marsh seems an unlikely place to learn about drought. This warren of narrow streams and muddy, reed-choked embankments clinging to the edge of the Hudson River twenty miles north of Times Square is the domain of crabs, worms, herons, and other water-loving creatures. But as Columbia University climatologist Dorothy Peteet paddles a narrow aluminum canoe deep into the marsh, she insists that buried deep in this black, sulphur-stinking muck are clues that could reveal when, and how badly, the nation's largest city will next be struck by crippling drought.
Here, she says, "we can get these climate records that we can't get anywhere else."
Some climate researchers tap ancient air bubbles trapped in Arctic ice to read long-lost atmospheres; some slice open stalagmites in tropical caves to measure 100,000-year-old rainfall. Peteet is on the hunt for pollen. She dredges up mud from as deep as 45 feet underground and hauls it back to her lab at the nearby Lamont-Doherty Earth Observatory. There she boils, bakes, and filters it to sift out pollen, not much thicker than a human hair, from plants several thousand years old. The relative abundance and variety of different species indicate climate conditions at the time the pollen was dropped: An uptick of dry-weather species like hickory and pine points to drought.
Pollen, and seeds like these, could shed light on how future droughts will impact New York City. Tim McDonnell/Climate Desk
2012 was the eighth or ninth warmest year on record, depending on which dataset you look at, according to the National Oceanic and Atmospheric Administration's annual State of the Climate report, released today. That is just one of many extreme statistics identified in the survey, which pulls together the most recent information from hundreds of researchers worldwide on everything from temperature to sea level to Arctic ice. Taken together, the report's authors say, the data paint an unmistakable picture of a warming planet.
"In 2012, certainly not every variable we looked at broke a record," Thomas Karl, the director of NOAA's climate data center, said. "I think what we've learned is one has to take a broad look at the climate system."
The heat map above, from the report, shows how 2012 temperatures compare to the average baseline of 1981-2010. While Alaska, parts of Asia, and elsewhere saw a cooler-than-average year, it was the hottest year on record in the contiguous United States (and, relatedly, an insanely expensive year for natural disasters), and temperatures in the Arctic are increasing twice as fast as the rest of the world. In June, Arctic sea ice minimums reached record lows, and over a two-day period in July more of the Greenland ice sheet was melting at once—97 percent—than ever seen before.
Another landmark was sea level rise: 2012 saw the highest global sea levels ever recorded, the peak of a trend that has seen seas rising just above a tenth of an inch per year over the last two decades. Interestingly, in the last couple years, melting ice (the black line in the graph at right) accounts for twice as much sea level rise as does thermal expansion of warming water (red line). And the sea wasn't just high, it was hot, too: Heat trapped in the top half-mile of the ocean remained near record highs. At the ocean surface, temperatures were among the 11 warmest on record, despite mostly flatlining since 2000 partly as a result of La Niña conditions that cool the sea.
Carbon emissions for the year were also their highest ever: In 2012, the world released roughly 9.7 quadrillion grams of carbon into the atmosphere, about one-tenth the weight of every living thing on Earth, pushing the atmospheric concentration higher, at least in some places, than at any time in human history. Other key greenhouse gases, including methane and nitrous oxide, also climbed from the previous year.
Sadly, all these shocking numbers weren't much of a shocker to the report's 384 authors from around the globe, NOAA's Karl said; they merely offer the latest bundle of proof that climate change is happening: "We see ongoing trends continuing."
This week the exiled head of the Syrian opposition movement said he would meet representatives of President Bashar al-Assad in Geneva, a promising turn for a conflict that has left 100,000 dead, including many civilians, since spring 2011. It has been a long, bitter battle, but for many Syrians one root of the violence stretches back to several years before al-Assad's troops began picking off anti-government protestors. Beginning in 2006, a prolonged, severe drought decimated farmland, spiked food prices, and forced millions of Syrians into poverty—helping to spark the unrest that eventually exploded into civil war.
The Syrian conflict is just one recent example of the connection between climate and conflict, a field that is increasingly piquing the interest of criminologists, economists, historians, and political scientists. Studies have begun to crop up in leading journals examining this connection in everything from the collapse of the Mayan civilization to modern police training in the Netherlands. A survey published today in Science takes a first-ever 30,000-foot view of this research, looking for trends that tie these examples together through fresh analysis of raw data from 60 quantitative studies. It offers evidence that unusually high temperatures could lead to tens of thousands more cases of "interpersonal" violence—murder, rape, assault, etc.—and more than a 50 percent increase in "intergroup" violence, i.e. war, in some places.
"This is what keeps me awake at night," lead author Solomon Hsiang, an environmental policy post-doc at Princeton, said. "The linkage between human conflict and climate changes was really pervasive."
Any cop could tell you that hot days can make people snap—last summer veteran police boss William Bratton argued that a warm winter contributed to a rash of murders in Chicago. But Hsiang and his colleagues wanted to see how this pattern held up across the globe, at different times and with different kinds of conflict, to gauge just how much the climate can lead to violence.
How will the world end? A giant meteor? Zombie apocalypse? Death Star target practice!? One scientist thinks our planet's death knell is going to be climate change, on an epic, terrifying scale...but, fortunately, not the kind we need to worry about.
The "runaway greenhouse"—which is thought to have happened on Venus in the past—is basically a climate change worst-case scenario: We reach a critical point where the atmosphere is so thick with greenhouse gases that no sunlight can escape back into space, the planet heats uncontrollably, the oceans evaporate completely, and things get, well, pretty uncomfortable, to put it mildly.
"Everything is really quite dead at that point," Colin Goldblatt, a planetary scientist at Canada's University of Victoria, says in a chipper English accent. Goldblatt has been working to understand whether a runaway greenhouse could ever happen on Earth. Scientists have long believed that even with extreme greenhouse gas concentrations, our sun simply doesn't heat the planet enough to trigger this effect. But using a series of custom computer programs that model incoming sunlight, greenhouse gas concentration, radiation absorbed by water vapor, and a host of other physical factors, Goldblatt has revised that threshold down, and in a paper published today in Nature Geoscience says that a runaway greenhouse could kick off with the amount of sunlight we get today.
"What we're seeing now is that if you pump the atmosphere full of carbon dioxide, you could make the planet so hot it would never be habitable again," he says. Taken to its conclusion, he explains, the runaway greenhouse would produce a new atmosphere with global temperatures around 2,420 degrees Fahrenheit, which would make even the Northeast heat wave of the last couple weeks feel like a vacation into a meat freezer.
So is it time to forget about rising sea levels and start to look for a new planet to inhabit before ours boils into the next Venus? Not quite. Goldblatt expects this kind of transformation to take place in about a billion years, regardless of human activity. The level of atmospheric carbon dioxide needed to tip the scales—about 30,000 parts per million, according to Goldblatt—is far beyond what humans are capable of contributing. Indeed, that's about 10 times what CO2 levels would be even if we quickly burned through all the remaining fossil fuels. (Right now we're at about 400 ppm, which is already bad.)
"There's no evidence that human action could cause this," Goldblatt says.