Blue Marble

Watch the World's Forests Disappear on Google Earth

| Thu Nov. 14, 2013 4:55 PM EST

Deforestation is a tricky problem to nail down. We know forests are shrinking, but knowing exactly where and by how much often means compiling locally reported data that can be shoddy, incomplete, or outdated, according to University of Maryland geographer Matthew Hansen. Better data would be an invaluable tool for resource managers looking to preserve trees, and for climate scientists who want to crunch how much carbon they can store, Hansen realized. So he set about to create the most high-resolution map of global forests ever made, partnering with Google Earth to process some 650,000 images taken by NASA satellites over the last decade.

The result, published today in Science, is a stunning series of time-lapse maps, along with an interactive mapping tool, that reveal the Earth lost about 888,000 square miles of forest between 2000 and 2012, roughly the area of the US east of the Mississippi River. The loss, which was most dramatic in the tropics, was primarily due to logging, urban development, strip mining, and other human impacts, Hansen said, but the figure also includes loss from fires, earthquakes, and other natural disasters. The maps are accurate to 11-square-mile units, close enough to see logging roads and individuals stands of trees, which gave the researchers an unprecedented look at the complete extent and rate of deforestation on a global and hyper-local scale.

In the exclusive video above, Hansen takes us on a tour of his new maps and the startling situation they reveal.

Producing super-detailed maps like these would have been impossible without Google's massive computer power; Hansen estimated his own computer would have taken 15 years to process all the images, while Google's servers churned them out in a few days. 

The data could be used to track the impact of forest protection policies, and hold a microscope to the forested areas most at risk.

"It's a big leap forward in terms of a set of facts, a set of observations on what this dynamic is," Hansen said.

One of the next steps, Hansen said, is to use the data to gauge exactly what this deforestation means for climate change. Trees are one of the largest "sinks" for carbon dioxide; previous studies suggest forests absorb a third of the carbon released by burning fossil fuels.

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Could Carl Sagan Have Defeated Climate Denial?

| Wed Nov. 13, 2013 12:03 PM EST
Carl Sagan with a model of the Viking lander.

Yesterday at the Library of Congress, a stunning list of science luminaries—from Bill Nye the Science Guy to Neil deGrasse Tyson to White House science adviser John Holdren—joined one extremely funny science aficionado (Family Guy creator Seth MacFarlane) to celebrate the late astronomer and television star Carl Sagan. The occasion was the opening of the "Seth MacFarlane Collection" of Sagan's personal papers: 1,705 boxes of Sagan's letters, notes, and writings now reside at the Library. The event also felt much like a preview of the coming Fox series Cosmos: A SpaceTime Odyssey, a remake of the show that made Sagan famous, that will be hosted by deGrasse Tyson and produced by MacFarlane and Sagan's widow, Ann Druyan.

One of the leading themes, however, was political. Speaker after speaker used the occasion to lament the way science is treated in the United States today, usually leading with the example of climate change. Science is suffering from "politicization on steroids," said MacFarlane. "We took a big, big hit when we lost Carl Sagan," he added later. Holdren remarked that Sagan "would have loved" President Obama's comment in June that when it comes to climate, "we don't have time for a meeting of the Flat Earth Society." Steven Soter, a writer on the original Cosmos series, added that Sagan would have been "appalled" by today's attacks on climate scientists, and that he would have "deeply altered the landscape" on the climate issue were he still alive.

Sagan died in 1996 after two years of struggling with myelodysplasia, a bone marrow disease. He was 62. During his life, he became the public face of science in the US and around the world thanks to the Emmy-award-winning Cosmos, which first aired on PBS in 1980 to great acclaim. He also published many widely read science books, campaigned for nuclear arms control and space exploration, and was a visionary who not only imagined what life might be like elsewhere in the galaxy but actually endeavored to search for it (a quest embodied in Sagan's novel Contact)—all the while denouncing UFO aficionados who failed to play by the rules of science and skepticism.

The notion that, today, Sagan would have been deeply engaged with the climate issue is highly plausible. In publicizing the threat of "nuclear winter" in the early 1980s, Sagan was basically outlining the possible consequences of a human-induced climate-alteration (albeit one that would freeze us rather than fry us). In fact, Sagan gained recognition as an astronomer for his research on the greenhouse effect of Venus, work that later inspired NASA climate researcher James Hansen.

Carl Sagan at the founding of the Planetary Society.
Carl Sagan at the founding of the Planetary Society. NASA JPL/Wikimedia Commons

And yet it doesn't take anything away from Sagan's unrivaled legacy to say that the problems we face today are perhaps too large even for him. The truth is that to celebrate what made Sagan so great and so successful as science's emissary to the public is to simultaneously realize why the challenges faced by science in the public arena today are so vast and intractable.

David Morrison, a doctoral student of Sagan's and an astrophysicist who now directs the Carl Sagan Center for Study of Life in the Universe at the SETI Institute, wondered aloud yesterday whether if he were alive today, Sagan would have been much more successful at fighting off nonsense than the rest of us. In answering the question, Morrison observed that in Sagan's heyday, the days of the Cosmos series, a few networks still dominated television. That meant that when Sagan was on TV (whether on PBS or doing one of his regular guest appearances on The Tonight Show Starring Johnny Carson), your chances were very high of actually seeing him, because there just weren't many other things to watch. By contrast, when the much-awaited Cosmos sequel airs on Fox, viewers will have the option of flipping to anything from reality cooking shows to paranormal pseudo-documentaries to politicized news.

For a brief trip down memory lane (and to see how science on TV used to look), here's the opening of the original Cosmos:

According to Fox, Sagan's Cosmos was ultimately seen by 750 million people. But nobody talking about science today gets the attention of audiences as vast as Sagan's, due to fundamental changes in the structure of the media.

At the same time, we can also see that some of the battles that Sagan engaged in the 1980s—over Ronald Reagan's "Star Wars" program and so-called nuclear winter—were dress rehearsals for the intense science politicization over issues like climate change that we live with today. In these conflicts, academic scientists and a few celebrity allies, like Sagan, clashed with conservative scientists affiliated with think tanks like the George C. Marshall Institute, who defended the science behind "Star Wars" and challenged nuclear winter.

That's still the basic blueprint for how political science conflicts play out, but perhaps as a result of so many of them, political conservatives in the US have grown increasingly distrustful of the scientific community, as documented in a recent study by sociologist Gordon Gauchat. This was not something Sagan had to face. Heading into the 1980s, surveys assessing public trust in science did not show a big difference between left and right:

Declining trust in science among conservatives since 1980.
Declining trust in science among conservatives since 1980. Gordon Gauchat

In other words, Sagan was a science communicator and a science hero in an era in which we weren't nearly as polarized over science, or sorted into politicized boxes due to our media choices. Today it's just different, and a whole lot harder. And thus while there is little doubt that Sagan's "heir apparent" (in MacFarlane's words), Neil deGrasse Tyson, is at least as talented as Sagan was, the overarching context has changed fundamentally.

The true challenge for science communication and outreach today, accordingly, is to figure out how to counteract these two momentous trends—let's call them politicization and fragmentation—and bring science to everybody once again.

MAP: Is Your State Ready for Climate Disasters?

| Tue Nov. 12, 2013 7:00 AM EST
climate readiness map
Tim McDonnell/Climate Desk

Whether it's wildfires in the West, drought in the Midwest, or sea level rise on the Eastern seaboard, chances are good your state is in for its own breed of climate-related disasters. Every state is required to file a State Hazard Mitigation Plan with FEMA, which lays out risks for that state and its protocols for handling catastrophe. But as a new analysis from Columbia University's Center for Climate Change Law reveals, many states' plans do not take climate change into account.

Michael Gerrard, the Center's director, said his team combed through all 50 reports to see how accurately and comprehensively climate change was taken into consideration, if at all, and grouped them into four ranked categories:

  1. No discussion of climate change or inaccurate discussion of climate change.
  2. Minimal mention of climate change related issues.
  3. Accurate but limited discussion of climate change and/or brief discussion with acknowledgement of need for future inclusion.
  4. Thorough discussion of climate change impacts on hazards and climate adaptation actions.

While FEMA itself acknowledged this summer that climate change could increase areas at risk from flooding by 45 percent overt the next century, states are not required to discuss climate change in their mitigation plans. The Columbia analysis didn't take into account climate planning outside the scope of the mitigation plans, like state-level greenhouse gas limits or renewable energy incentives. And as my colleague Kate Sheppard reported, some government officials have avoided using climate science terminology even in plans that implicitly address climate risks; states that didn't use terms like "climate change" and "global warming" in their mitigation plans were docked points in Columbia's ranking algorithm.

Gerrard said he wasn't surprised to find more attention paid to climate change in coastal states like Alaska and New York that are closest to the front lines. But he was surprised to find that a plurality of states landed in the least-prepared category, suggesting a need, he said, for better communication of non-coastal risks like drought and heat waves.

"We had hoped that more of the states would have dealt with [climate change] in a more forthright way," he said.

"Bodies are lined up in the streets"

| Tue Nov. 12, 2013 1:44 AM EST
Marines carry an injured Filipino woman on a stretcher for medical attention, assisted by a Philippine Air Force airman at Vilamore Air Base, Manila. Caleb Hoover/U.S. Marines/ZUMA

A difficult recovery effort, hampered by security threats, bottlenecks, and an almost complete lack of communications, is still in its infancy in the Philippines four days after a powerful typhoon plowed through the country.

Super Typhoon Haiyan—also known locally as Yolanda—made landfall several times on Friday, leaving in its wake up to 10,000 casualties (a figure that comes from local officials on the island of Leyte and reported by the Associated Press; the official Philippine government count is much lower). The Joint Typhoon Warning Center data reported sustained winds approached 195 miles per hour three hours before landfall, with gusts of up to 235 miles per hour. Stunningly scary footage captured by a CCTV/Weather Channel team during Haiyan's height shows damaging storm surges ripping buildings apart, "like a tsunami." The storm made landfall again in Vietnam on Monday morning local time.

The Philippines, a group of more than 7,100 islands, is no a stranger to tropical cyclones (this is the 24th just this year). And just as more than 9.5 million people who were in the storm's path survey the damage and locate loved ones, the country is facing another tropical depression, Zoraida​.

"We are always between two typhoons. The farther we are from the previous one, the nearer we are to the next one."

"We are always between two typhoons. The farther we are from the previous one, the nearer we are to the next one," said Amalie Obusan, a Greenpeace climate campaigner in the Philippines, by phone. "Now it seems like a very cruel joke…Every year, every super typhoon is much stronger than the previous year."

Lynette Lim from Save the Children, an aid and development agency focused on the youngest disaster victims, survived the storm in the provincial capital Tacloban, perhaps the hardest hit city. She said the severity of Haiyan took everyone by surprise, scrambling preparation efforts, and setting the recovery back. "Most of the government officials were completely incapacitated to respond to the needs of children and their families." Even now, four days later, Lim said, "We're really starting from scratch."

Lim estimates that two out of every five dead bodies she saw were children. Reached by phone in Manila, where she had returned to help coordinate her organization's response with the benefit of cellphone reception, Lim said she saw "widespread" evidence of malnutrition amongst children already hungry just days after the storm: "It's just quite a heartbreaking sight. Going without food for this many days could be fatal for them." 

One of the most pressing concerns facing the recovery effort, said Lim, is installing proper management of camps for survivors. In Tacloban's main sports arena, known as the Astrodome, which she said was housing an estimated 15,000 people, "the conditions are terrible because people are throwing their trash everywhere, and children are openly defecating because there are no portable toilets."

But relief resources cannot start flowing reliably until basics are met, and that's going to take time: "Clearing the roads, there is no power, there is no water," she said. "It's really tough conditions for aid workers as well as for the survivors."

PHOTOS: Devastation in the Philippines After Haiyan Hits

| Mon Nov. 11, 2013 1:05 PM EST

Super Typhoon Haiyan, perhaps the strongest storm ever recorded on Earth, made landfall in the Philippines on Friday. The result was catastrophic, with 10,000 feared dead, according to the Associated Press. The storm made landfall again in Vietnam on Monday morning local time. Here are photos of the preparation for, and aftermath of, Haiyan's arrival.

A child wraps himself in a blanket inside a makeshift house along a fishing village in Bacoor, south of Manila. Ezra Acayan/ZUMA

 
Various government agencies monitor the path of Super Typhoon Haiyan inside the National Disaster Risk Reduction and Management Council (NDRRMC) office in Quezon City, Philippines. Rouelle Umali/ZUMA
This NASA MODIS Aqua satellite image shows Super Typhoon Haiyan shortly before it smashed into the Philippines with 200 mph winds and 50-foot waves. Lightroom Photos/Nasa/ZUMA
 
Dark clouds from Super Typhoon Haiyan loom over the skyscrapers of metro Manila. Rouelle Umali/ZUMA

 

People reinforce dykes ahead of Super Typhoon Haiyan in Phu Yen province, central Vietnam. Vna/ZUMA

 

Local residents are evacuated to safe places before Super Typhoon Haiyan hit Vietnam in Da Nang city, central Vietnam. Vna/ZUMA

 

Aerial photo taken on November 10 shows the scene after Typhoon Haiyan hit Leyte Province, Philippines. Ryan Lim/ZUMA

 

Aerial photo shows the scene after Typhoon Haiyan hit Leyte Province. Ryan Lim/ZUMA

 

Filipino typhoon survivors from Tacloban City disembark from a C130 military plane in an airport in Cebu City, Philippines. Ritchie Tongo/ZUMA

 

 

Look What's Slowing Down Global Warming

| Sun Nov. 10, 2013 2:00 PM EST

Climate deniers like to point to the so-called global warming "hiatus" as evidence that humans aren't changing the climate. But according a new study, exactly the opposite is true: The recent slowdown in global temperature increases is partially the result of one of the few successful international crackdowns on greenhouse gases.

Back in 1988, more than 40 countries, including the US, signed the Montreal Protocol, an agreement to phase out the use of ozone-depleting gases like chlorofluorocarbons (today the Protocol has nearly 200 signatories). According to the EPA, CFC emissions are down 90 percent since the Protocol, a drop that the agency calls "one of the largest reductions to date in global greenhouse gas emissions." That's a blessing for the ozone layer, but also for the climate. CFCs are a potent heat-trapping gas, and a new analysis published today in Nature Geoscience finds that slashing them has been a major driver of the much-discussed slowdown in global warming.

"The recent decrease in warming, presented by global warming skeptics as proof that humankind cannot affect the climate system, is shown to have a direct human origin."

Without the Protocol, environmental economist Francisco Estrada of the Universidad Nacional Autónoma de México reports, global temperatures today would be about a tenth of a degree Celsius higher than they are. That's roughly an eighth of the total warming documented since 1880.

Estrada and his co-authors compared global temperature and greenhouse gas emissions records over the last century and found that breaks in the steady upward march of both coincided closely. At times when emissions leveled off or dropped, like during the Great Depression, the trend was mirrored in temperatures; likewise for when emissions climbed.

"With these breaks, what's interesting is that when they're common that's pretty indicative of causation," said Pierre Perron, a Boston University economist who developed the custom-built statistical tests used in the study.

The findings put a new spin on investigation into the cause of the recent "hiatus." Scientists have suggested that several temporary natural phenomena, including the deep ocean sucking up more heat, are responsible for this slowdown. Estrada says his findings show that a recent reduction in heat-trapping CFCs as a result of the Montreal Protocol has also played an important role.

"Paradoxically, the recent decrease in warming, presented by global warming skeptics as proof that humankind cannot affect the climate system, is shown to have a direct human origin," Estrada writes in the study.

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Carbon-Sucking Golf Balls and Other Crazy Climate Patents

| Fri Nov. 8, 2013 7:00 AM EST

Forget YouTube as your go-to 3:00 p.m. internet distraction. For me, it's the US patent office website. There is some seriously wild stuff being invented by your fellow citizens, not least in the area of climate change mitigation and adaptation. Here are a few of my favorite climate-related patents issued recently by the office. (I've added a little color to the design sketches):

Golf courses are hardly known for being paragons of environmentally friendly land use. They use a massive amount of water and have been found to be net carbon emitters, mainly due to land-clearing. But—phew!—there could soon be a way to shuck that green guilt and keep on swinging.

These carbon dioxide-absorbing golf balls, invented by the golf team at Nike, are intended to "reduce atmospheric carbon dioxide levels to aid in alleviating global warming," by enabling the "golf ball itself to play a role in the fight against global warming." (You can't make this stuff up). Additionally, the Nike inventors claim this is the first time a golf ball itself has attempted to off-set carbon consumed during its manufacture.

Here's how it works: When you hit the ball, little bits of its surface layer deform and set off a chemical chain reaction that absorbs carbon dioxide as the ball flies through the air. The more times you swing, the greater the surface area exposed to the internal reactions. So, if you're anything like me, and you need to hit the ball an embarrassing number of times, comfort yourself with the knowledge you're doing more to save the world more than your pro golf buddies (except all my balls end up in the water). At the end of the game, according to the patent, you'll be able to see how much carbon you've sequestered using a visual indicator on the side of the ball. 

Golfing sure beats hammering out a broad international agreement to reduce carbon. But sorry to spike your high: The inventors admit the golf ball could "at best be only carbon neutral, and is not capable of reducing the total amount of carbon dioxide in the atmosphere." Damn. Really? (After several attempts to organize an interview with the Portland-based inventor Chia-Chyi Cheng, Nike told me the company doesn't talk to the media about their numerous inventions or patents).

Verdict: Cool science! But don't expect President Obama to start arguing his golf days are saving the planet.

 

We learned last month that average summer temperatures in parts of the Arctic during the past 100 years are hotter than they have been for possibly as long as 120,000 years. And the Arctic recently registered the sixth lowest summer sea ice minimum on record.

Why don’t we just replace all that melting ice?

That's the idea behind this recently published patent for artificial ice. According to the filing, an "ice" substrate would be dropped onto the surface of an ocean or a lake and left there to reflect sunlight back into the atmosphere using a 3-corner retro reflector surface (the same technology used by street signs). Meanwhile, nutrients sown on the underside would encourage algae to grow for biofuel production. Algae is a proven energy source. In February 2012, President Obama announced the Department of Energy would allocate $14 million in new funding to develop transportation fuels from algae.

"It seemed like a two-fer to me," says inventor and engineer Phillip Langhorst from St. Louis, Missouri. "In order to solve global warming we're going to have to do something on an insanely huge scale. And this is the only thing I've seen that's big enough." 

A few weeks after putting the ice on the water, a ship would come along, scrape the algae off and reapply the necessary nutrients.

"I need help, obviously, to see if this is a viable scheme," he says, although he admits most companies he approaches balk at the idea. But he argues that facing the realities and costs of big geo-engineering projects like this is becoming increasingly necessary, in lieu of putting a price on carbon: "Pick your poison, you know," he says. "My goal is not so much to patent this and make a billion dollars off of it; it's to solve the global warming issue so we all don't have to move to Saskatchewan​."

Verdict: Please, can't we stop the real ice from melting?

 

Imagine this scenario in the not-too-distant future: Your car has iced over in one of the many more extreme storms of a climate-changed world. It takes too long—and too much gas—to de-ice the car. Moreover, the engines in energy-efficient and electric cars mean there is less "waste heat" in the system that's available for the purpose of traditional defrosting techniques.

A new defrosting system may just become the must-have for winter drivers, according to this patent for a "windshield washer fluid heater and system," which attempts to defrost within seconds, not minutes. It may even, according to the language of the patent, reduce "energy dependence on foreign oil." That actually isn't too lofty a claim when you look at the auto industry roaring back to life. Since 2009, car production has nearly doubled; in July, US car and light-truck sales ran at an annualized pace of 15.8 million, up more than a million from the previous year. Any fuel savings count.

The invention passes engine heat that already exists through a new heat exchanger. Upon flicking the washer/wiper switch, washer fluid heats in a special new heater in a matter of seconds, and finally sprays out nozzles integrated into the wiper blades of the car, delivering a "continuous on-demand heated fluid deicing and cleaning action to the windshield and wiper blades." 

"This is so much more effective in clearing the windshield, because a traditional system needs to warm up 30-40 pounds of windshield glass before it can get to the outside ice," which requires a lot of energy, says Jere Lansinger, a 74-year-old retired automotive engineer and inventor. A 40-year veteran of the industry in Detroit, Lansinger used to test defrosting systems to ensure they met the federal standard for safe driving: around 30 minutes for a clear windshield. "And 30 minutes is a terribly long time when you want to get moving in the morning." So for the last 20 years he's been tinkering on this invention in his garage. Now the defrost time is under a minute, he says.

Lansinger has commercial interest already. The invention has been bought by TSM Corporation, Michigan, and is being developed as a product called QuikTherm, which the company says is currently being tested at several North American automotive parts manufacturers. And that's enormously gratifying for Lansinger. "Frankly it makes me feel better than any big royalties I'll get."

Verdict: ​A neat fuel-efficiency measure I've never thought about. And nothing's worse than de-icing your car.

 

This might be my favorite for its simplicity: A portable power station that can be off-loaded from a trailer, unfolded, put up anywhere there's sun or wind, and switched on. In the picture here, it's being used to charge a car. But it can power anything it likes.

"I was tickled to death," says Lynn Miller, the inventor from Crossville, Tennessee, about the day he was granted the patent, which he's been working on for over three years. He's now spent over $20,000 on the idea and is looking forward to getting a prototype up and running in the new year.

For Miller, it's all about simplicity and reducing costs for the consumer. "We'd bring it out in the morning, and in the afternoon it's working. It's a plug-and play-system," he says. He also likes the idea that having one of these in the company parking lot, or by the side of the road, gives ultimate green bragging rights: "It's very visible, it reminds people day-in, day-out that you're environmental."

Miller's plan is to also set up the portable power stations at schools and colleges to demonstrate the benefits of renewable energy. "It's not just book knowledge, this can be turned into a classroom."

Verdict: I want one.

Thousands Feared Dead After Super Typhoon Haiyan Devastates Philippines

| Thu Nov. 7, 2013 8:54 PM EST
Devestation in Tacloban, Philippines, caused by Typhoon Haiyan.

Update (11/10/13): Thousands are feared dead after Typhoon Haiyan slammed into the Philippines Friday. Government officials are estimating that 10,000 people died in Leyte Province, in the eastern part of the country, according to the Associated Press.

The 13-foot storm surge left the coastal city of Tacloban "in ruins," according to the New York Times. "There is no power, no water, nothing," Voltaire Gazmin, the country's defense secretary, reportedly said of the situation in Tacloban. "People are desperate. They're looting."

Haiyan made landfall once again Monday morning local time, hitting northern Vietnam with 75 mile-per-hour winds.

Super Typhoon Haiyan
Super Typhoon Haiyan as it made landfall in the Philippines.  NOAA

By at least one measurement, it appears that Super Typhoon Haiyan, which just slammed into the Philippine island of Samar, may be the strongest storm reliably recorded on Earth. Additional measurements and analysis will surely be necessary to confirm this, but for now, here's what we know:

The US Navy's Joint Typhoon Warning Center, which tracks typhoons and Super Typhoons—the most powerful storms on the planet—estimated Haiyan's maximum one-minute sustained winds at 170 knots, which translates into about 195 miles per hour. 

According to meteorologist Jeff Masters, a number of Pacific storms prior to 1969 were measured with wind speeds equal to or above 170 knots, but these estimates are now considered unreliable. Since 1969, the three strongest storms on record by wind speed all had winds of 165 knots, or 190 miles per hour: 1979's Super Typhoon Tip, 1969's Atlantic Hurricane Camille, and 1980's Atlantic Hurricane Allen. Haiyan just passed all three by this metric, though Masters notes that there is less confidence in Haiyan's true intensity, since Tip, Camille, and Allen were all investigated by hurricane hunter aircraft. Haiyan's intensity has only been estimated based on satellite images (you can read more about how these satellite measurements are done, and why Haiyan presented such a stunning satellite image, in this great New Republic article by Nate Cohn).

There are some additional caveats here: Wind speeds are only one way of determining a storm's intensity. Another is measuring its minimum central pressure, and here Tip still reigns supreme, with a minimum central pressure of 870 millibars.

Most disturbing of all is another record: At landfall, Haiyan was more intense than any other landfalling storm.

Is it possible that Haiyan was a "Category 6" hurricane? Officially, the Saffir-Simpson hurricane scale defines the category 5 range (the highest category) as beginning at 137 knots. But once you're 33 knots above that, as Haiyan was, perhaps the scale has been superseded. After all, the entire Category 2 range only spans 12 knots.

Bill de Blasio's Biggest Challenge: Climate Change

| Wed Nov. 6, 2013 4:43 PM EST

This story first appeared on the Grist website and is reproduced here as part of the Climate Desk collaboration.

Bill de Blasio, New York City's new mayor-elect, didn't spend much time during the campaign talking about climate change, but he'll likely spend a lot of his time at City Hall dealing with it.

New York finds itself these days with an unusual conundrum: Its biggest problems are largely the byproduct of its biggest successes. Just 20 years ago, New York was, like American cities generally, blighted by rampant crime and less populated than at its mid-century heyday.

Today, New York City's central challenge is one that virtually any other city would love to have: Too many rich people want to live there. But Wall Street bankers, trust funders, and wealthy foreigners looking for a pied-à-terre have driven up the price of housing to levels that threaten to eject the creative classes that have powered New York's renaissance. The high cost of housing is also the main reason New York's homeless population is at an all-time high.

The massive gap between rich and poor, the loss of diversity in the most centrally located neighborhoods, and the lack of affordable housing were the problems identified by de Blasio in his "tale of two cities" campaign spiel. De Blasio won in a landslide Tuesday on a promise to increase the supply of affordable housing, raise taxes on the very wealthy, and expand educational opportunities for those left behind by New York's current boom. Meanwhile, crime has been so successfully tamed—the murder rate is one-fifth of its 1991 peak—that de Blasio has proposed to reduce the use of aggressive policing tactics such as stop-and-frisk.

But other serious challenges loom in New York's future, even though they were hardly mentioned in this year's mayoral campaign. Indeed, they are arguably already here: extreme weather events caused by climate change, and felt especially hard in coastal areas developed during the city's boom years.

New York is built on a collection of islands, with 520 miles of coastline and entire neighborhoods constructed on landfill. One year ago, Hurricane Sandy flooded New York's low-lying neighborhoods, from Lower Manhattan to the Rockaways in southeastern Queens, leaving elderly, impoverished New Yorkers stranded in high-rise housing projects without power for weeks. Some families are still displaced, living seven to a hotel room.

Global warming leads to melting polar ice caps, which lead to higher sea levels. Global warming is also raising surface water temperatures, leading to larger, more frequent storms. The former could permanently submerge miles of New York's currently inhabited land, while the latter threatens to periodically topple buildings, destroy power stations, and knock trees onto cars.

New York Harbor is where the Hudson River meets the Atlantic Ocean, and what we call the East and lower Hudson Rivers are actually tidal estuaries. Much of New York's recent economic and real estate development has been in the very same waterfront areas that are most at risk from climate change. Tribeca, DUMBO, and Red Hook have seen former waterfront warehouses filled first with artists and then well-heeled professionals. A year ago, they saw neck-high water flowing through their streets.

Mayor Mike Bloomberg, aware of the urgent need for housing, has encouraged the development of New York's waterfront neighborhoods. After Sandy, the Bloomberg administration created the Special Initiative for Rebuilding and Resiliency, which produced a massive report, released in June. The report found that the next hurricane could be even worse: "With greater winds and more rain, Sandy could have had an even more serious impact on the areas of Staten Island, Southern Brooklyn, and South Queens that experienced the most devastation during the storm. And while Sandy brought the full force of its impact at high tide for these southernmost areas of the city, it hit the area around western Long Island Sound almost exactly at low tide. As a consequence, parts of the Bronx, Northern Queens, and East Harlem were not as affected as they could have been."

But Sandy was plenty bad and its effects will last for years to come. On Monday, The New York Times reported that the Metropolitan Transit Authority will be forced to continue cutting back service and spending billions of dollars for years to come to deal with the damage Sandy wrought. While the MTA got the subways running again within days, it has recently had to shut down stretches of the R and G lines to repair tunnels that were flooded. There will be an estimated $3 billion worth of repair work for each of the next two years, about double what would otherwise have been needed.

New York cannot afford to be unprepared for climate change. As Bloomberg's report lays out, the city must invest in a wide array of both hard and soft anti-flooding infrastructure improvements. Buildings must be elevated, shorelines must be regraded, beachfront boardwalks must be rebuilt with gradual rises in elevation. Buildings must move their power supplies upward, while neighborhoods must move their power lines downward, wrapping them in water-resistant materials. Sidewalks will have to be made permeable, to wick floodwater back out to sea. Meanwhile, the city must continue its efforts to be a global leader in reducing its own carbon footprint.

Though he vaguely promised to adhere to Bloomberg's climate change agenda, de Blasio didn't make climate preparedness an issue in his campaign. But it will likely be the central challenge of his mayoralty, and his successor's as well.

De Blasio said in his victory address that "the city has chosen a progressive path" in electing him. If he really wants to help all New Yorkers thrive, he'll get as serious about climate change as he is about economic inequality. Reducing the city's greenhouse gas emissions and preparing its neighborhoods for storms and rising seas is a moral obligation for a self-described progressive, no less so than housing the city's homeless, enhancing its social mobility, or welcoming its undocumented immigrants. And climate adaptation is a pragmatic imperative too. It will be expensive, but as Sandy demonstrated, failure to invest on the front end will cost even more later on.

Why Dengue and Yellow Fever Could Be Coming to a City Near You

| Mon Nov. 4, 2013 7:00 AM EST

Estimated Population at Risk for Dengue Fever in 1990 (A) and 2085 (B) Based on Climate Data from 1961 to 1990

This past summer, Aedes aegypti—the invasive African mosquito best known for carrying the potentially deadly diseases dengue and yellow fever—made its unexpected debut in California, squirming up from Madera to Clovis to Fresno and the Bay Area.

For a blood-sucking nightmare, Aedes aegypti is surprisingly attractive: Its dark skin and bright white polka-dots make it hard to miss. Unfortunately, it is also notoriously difficult to control. According to the Centers for Disease Control and Prevention (CDC), Aedes aegypti can lay its eggs in less than a teaspoon of liquid and survive without water for months.

While Aedes aegypti has long resided in Texas and the southeastern United States, this is the first time it's reached California. News outlets have covered the story extensively, but few have mentioned climate change's role in the mosquito's spread. The CDC says it's "likely that Ae. aegypti is continually responding or adapting to environmental change." In a 2012 report, the World Health Organization (WHO) pointed out that "temperatures, precipitation and humidity have a strong influence on the reproduction, survival and biting rates" of Aedes aegypti.

Climate change studies predict that dengue—which infects as many as 100 million people a year—will expose an additional 2 billion by 2080. In 2009, the mosquito kicked off a Florida outbreak of dengue in a state that hadn't seen the disease in more than 70 years, and Thailand is currently undergoing its worst dengue epidemic in more than 20 years.

Dengue's initial symptoms often resemble the flu, but advanced infections—which cause lung and heart problems, severe abdominal pain, and bleeding from the nose and mouth—kill 15,000 people in 100 countries annually.

Yellow fever is no picnic, either: The disease was one of the world's most feared before the development of a vaccine in 1936. Its name comes from the illness' trademark jaundice, and it also causes severe stomach bleeding (often resulting in black vomit). It kills 15 percent of those infected and closer to 50 percent when left untreated.

In the past, yellow fever in the United States made its way as far north as New York City. In 1793, an outbreak even wiped out 10 percent of Philadelphia. Luckily, citizens figured out that they could stop its spread by overturning containers of standing water where mosquitoes bred, and yellow fever was largely eradicated in the United States. In the last 40 years, there have been only nine cases of yellow fever in the United States, all of which were contracted abroad. But in Africa and Central and South America, it's a much bigger problem: Roughly 200,000 new cases of yellow fever occur every year. Over the last 20 years, outbreaks have occurred in more countries with more frequency, especially in sub-Saharan Africa. In 2010, Uganda had its first outbreak in more than 40 years. WHO reports the increasing number of cases is likely linked to climate change.

There is no vaccine for dengue, and American citizens typically do not get vaccinated against yellow fever unless they travel to a region where it's endemic. So far, there have been no cases of dengue or yellow fever connected to California's new Aedes aegypti, and none of the insects have tested positive for the diseases. But public health officials remain vigilant. "We were shocked," one insect control official in Madera, California, told the Los Angeles Times. "We never expected this mosquito in California."