Studying a Polar Menagerie
On an Island in Arctic Russia
Ninety miles from the Russian mainland and 300 miles above the Arctic Circle, Wrangel Island is home to an eclectic assortment of fauna and flora — muskoxen,
Second in a series of blog posts from the Russian Arctic
polar bears, wolves, reindeer, wolverines, walruses, Asia’s only population of snow geese, and 417 plant species. Joel Berger, a field biologist with the Wildlife Conservation Society and the University of Montana, spent several weeks on Wrangel Island this spring. In the second of three blog posts for e360
, he describes the arduous conditions under which Russian and U.S. scientists collect data on the island’s odd assortment of creatures. Read more.
14 Apr 2014:
Despite Stark Warnings,
UN Panel Finds Signs of Hope on Climate
Although greenhouse gas emissions continue to rise at an alarming rate, governments are beginning to embrace carbon-cutting initiatives, while technological advances are sharply reducing the cost of deploying solar and wind power, according to the latest report by the Intergovernmental Panel on Climate Change.
The working group report on climate mitigation
, released in Berlin, said that global CO2 emissions have risen about 2.2 percent a year this century — twice the rate of the last few decades of the 20th century — and that holding temperature increases to 2 degrees C (3.6 F) can only be achieved through an intensive push over the next 15 years. But the report also said that the political will to reduce carbon emissions seems to be rising around the world, and that shifting the global energy system from fossil fuels to zero- or low-carbon sources would reduce economic growth by only about .06 percent per year.
“The loss in consumption is relatively modest,” said IPCC chairman Rajendra Pachauri. “The longer we delay the higher would be the cost.”
On Far-Flung Wrangel Island,
A Scientist Sizes up Muskoxen
As a field biologist for the University of Montana and the Wildlife Conservation Society, Joel Berger has been to his share of end-of-the-earth places. But few have
Muskoxen on Wrangel Island
rivaled Wrangel Island, the rugged, frozen outpost located 300 miles above the Arctic Circle in Russia’s extreme Far East. In the first of three reports for Yale e360
, Berger describes the arduous trip to Wrangel and the scientific work that has taken him there — research with Russian colleagues on the island’s 900 muskoxen, a shaggy beast that is a relic from the Pleistocene era. In subsequent reports, Berger will describe the motley assortment of wildlife that has colonized Wrangel and the contrasting impacts of climate change on eastern Siberia and Arctic Alaska.
07 Apr 2014:
Newfound Atmospheric 'Hole'
Threatens Polar Ozone Layer, Scientists Say
Researchers have discovered
a large opening in the Earth's atmosphere that is enabling pollutants to rise
Pacific atmosphere hole an elevator to the stratosphere
into the stratosphere and destroy ozone. The hole, which is in a part of the lower atmosphere called the "OH shield," is several thousand kilometers long and is centered over the tropical west Pacific Ocean. It's relatively close to Southeast Asia, a region with a booming population and rapidly increasing air pollution. The hole is a major concern because the OH shield usually scrubs air of chemical compounds emitted near the ground before they can reach the stratosphere, where those compounds can persist for long periods of time, reacting with and destroying ozone, say researchers at Germany's Alfred Wegener Institute who identified the hole. The newly discovered phenomenon acts as a sort of elevator, researchers say, drawing chlorofluorocarbons, sulfur dioxide, and other contaminants straight up to the stratosphere and bypassing the OH shield scrub.
E360 Announces Contest
Yale Environment 360
For Best Environmental Videos
is holding a contest to honor the best environmental videos. Entries must be videos that focus on an environmental issue or theme, have not been widely viewed online, and are a maximum of 15 minutes in length. The first-place winner will receive $2,000, and two runners-up will each receive $500. The winning entries will be posted on Yale Environment 360
. The deadline for entries is June 6, 2014. Read further contest information.
03 Apr 2014:
Deforestation of Sandy Soils
Increases the Release of CO2, Study Finds
The texture of the soil that microbes live in determines how much carbon they release after deforestation, with sandy soils sending the most carbon into the atmosphere, according to research
led by Yale scientists.
Soils most affected by forest loss in red; least in yellow.
Subterranean microbes regulate carbon emissions from soil, and drastic changes to the microbial community, such as those that follow deforestation, can allow more CO2 to escape into the atmosphere and exacerbate global warming. The texture of soil, rather than such factors as temperature or nutrient concentrations, was the most important factor governing the release of CO2, the researchers found. Muddy, clay-like soils provide the most stable environment for microbial communities, likely because they're better at retaining nutrients than loose, sandy soils. The team used the findings to map areas in the U.S. where soil microbial communities would be most and least affected by deforestation, which could help inform land management practices.
Comment: e360 Point/Counterpoint Debate
On University Fossil Fuel Divestment
Scientists Charles H. Greene, of Cornell University, and Daniel M. Kammen, of the University of California, Berkeley, offer commentary on the recent Yale Environment 360 Point
articles on the
Student protest at Tufts University last spring
issue of whether universities should take a stand against climate change by divesting from companies that produce oil, natural gas, or coal. Greene and Kammen make the case that the movement to divest is gaining ground on U.S. campuses and will eventually succeed because fossil fuels are increasingly seen as a potentially risky investment. "We predict that divestment at the nation’s colleges and universities will occur much more rapidly than anybody imagined at the start of the campaign just over a year ago," they write. Read their comment.
31 Mar 2014:
IPCC Issues Stark Report
On Present and Future Climate Impacts
Rapidly rising levels of greenhouse gases are already having a major impact on the earth’s natural systems and the problem is likely to grow significantly worse
unless these emissions are brought under control, according to a new report by the Intergovernmental Panel on Climate Change (IPCC). The report
, released in Yokohama, Japan, said that steadily rising temperatures are melting polar ice caps, sharply diminishing Arctic sea ice, intensifying heat waves and heavy rains, causing the death of coral reefs, and placing water and food supplies under stress. The report on climate impacts, drafted by several hundred of the world’s leading climate scientists, emphasized that the world’s food supply is at considerable risk. Already, the report said, heat waves and water stress are affecting the output of wheat and corn on a global scale, impacts that are only expected to intensify in the future, further exacerbating food shortages. “Nobody on this planet is going to be untouched by the impacts of climate change,” said IPCC chairman Rajendra K. Pachauri.
28 Mar 2014:
West Antarctic Glacial Loss
Is Rapidly Intensifying, New Study Shows
Six massive glaciers in West Antarctica are dumping far more ice into the Southern Ocean than they were 40
An 18-mile crack in the Pine Island Glacier
years ago and now account for 10 percent of the world’s sea level rise
, according to a new study. Reporting in Geophysical Research Letters
, an international team of scientists said that the amount of ice draining from the six glaciers has increased by 77 percent since 1973. The scientists said that the ice loss from the six glaciers is so substantial that it equals the amount of ice draining annually from the entire Greenland Ice Sheet. The scientists used satellite data from 1973 and 2013 to gauge the ice loss from the six glaciers. The Pine Island Glacier
is moving more rapidly to the sea than any of the other six, with its speed increasing from 1.5 miles per year in 1973 to 2.5 miles per year in 2013. The glaciers are dumping more ice into the sea primarily because warmer ocean waters are loosening the ice sheets’ hold on the sea floor, which speeds up glacial flow.
Five Questions for Mario Molina
On Climate Science’s PR Campaign
The American Association for the Advancement of Science (AAAS), the world’s largest scientific society,
recently launched the “What We Know”
campaign, designed to cut through the fog of misinformation about climate change and convey to the public the current state of climate science. Chairing that effort is Mario J. Molina, a chemist who won a 1995 Nobel Prize for his work on the threat to the world’s ozone layer. Yale Environment 360
asked Molina five questions about the AAAS campaign and why it might succeed where previous efforts have failed.
20 Mar 2014:
The 2013-2014 Winter Was
The 34th Coldest on Record in U.S., NASA Says
Although many residents of eastern North America may feel like they’ve just suffered through a winter of record cold, the fact is that the winter of 2013-2014 was only
the 34th coldest in 119 years of record keeping in the U.S. As this map
from the U.S. National Climatic Data Center shows, temperatures in the eastern and southern U.S. from Dec. 1, 2013, to Feb. 28th, 2014, were as much as 8 degrees C (14 F) colder than the 2000 to 2013 average for those months. But the western U.S. and Alaska saw unusually warm weather, with California experiencing its hottest winter on record. Overall, temperatures this past winter in the U.S. were about 1 degree F above average. Meanwhile, temperatures in Russia, Asia, and much of Europe were well above average this winter, and land temperatures globally for December, January, and February were the 10th warmest on record.
19 Mar 2014:
CO2 Levels Have Crossed
400 ppm Threshold Far Earlier This Year
Concentrations of carbon dioxide in the atmosphere have reached the 400 parts per million threshold two months earlier this year than last, an indication that the planet will soon experience the 400 ppm level year-round, according to
scientists from the Scripps Institute of Oceanography. Last year was the first time in hundreds of thousands of years that the 400 ppm threshold was crossed. Scripps scientists expect
CO2 levels to hover around 400 ppm for the next two months, when the Northern Hemisphere spring will go into full bloom and plants will suck CO2 from the atmosphere until going dormant in the fall. "It’s just a matter of time before it stays over 400 forever," said Ralph Keeling, who took over the CO2 monitoring program from his father, Charles David Keeling, who started it in 1958. Since then, atmospheric CO2 levels have risen steadily from 313 ppm as the world continues to burn fossil fuels. Scientists estimate it's been 800,000 to 15 million years since the planet has seen concentrations this high.
18 Mar 2014:
Wildflower Season in Rockies
Is 35 Days Longer as Climate Warms
A warming climate has extended the wildflower season in the Rocky Mountains by 35 days since the 1970s,
according to a 39-year study of more than two million blooms. The bloom season, which used to run from late May to early September, now lasts from late April to late
Crested Butte, Colorado
September, the researchers say. Previous, less extensive studies seemed to indicate most wildflowers simply shift their bloom cycles to earlier in the year, but new findings
published in the Proceedings of the National Academy of Sciences
show that the changes are more complex, with the flowers reaching peak bloom sooner and flowering later in the year. The shift in the timing of blooms could have a major impact on pollinating insects and migratory birds. For example, hummingbirds that summer in the Rocky Mountains time their nesting so that their eggs hatch at peak bloom, when there is plenty of flower nectar for hungry chicks. As the bloom season lengthens, the plants are not producing more flowers. The same number of blooms is spread out over more days, so at peak bloom there may be fewer flowers and less food for hummingbirds, the researchers say.
17 Mar 2014:
Northeast Greenland Glaciers
Are Now Melting Rapidly, Study Finds
The glaciers of northeast Greenland, long thought to be the most stable part of the massive Greenland ice sheet, are melting at an accelerating pace, losing roughly 10
billion tons of ice annually for the past decade, say researchers
from the U.S. and Denmark. The finding will likely boost estimates of global sea level rise, which had previously not accounted for massive ice loss from that region, scientists say. The Zachariae ice stream in northeast Greenland, which drains 16 percent of the ice sheet, has retreated roughly 12.4 miles in the past decade, outpacing the fast-moving Jakobshavn glacier, which has retreated 21.7 miles over the last 150 years. Ice loss from the region is likely accelerating, the researchers say, because ice dams in nearby bays that had been blocking the glaciers' paths are now also melting, freeing the way for the glaciers to flow into the ocean.
14 Mar 2014:
Major Winds Have Lashed
North Atlantic This Winter, NOAA Map Shows
Forty-three hurricane-force winter storms have lashed the North Atlantic since late October, boosting the region's average wind speed in January and February by more than 12 miles per hour, as shown in this map
the U.S. National Oceanic and Atmospheric Administration (NOAA). The blue colors indicate areas where wind speeds exceeded the 1981-2010 average; browns indicate winds that were lower than average. In the North Atlantic, an unusually high number of hurricane-force storms, with winds exceeding 74 mph, battered southeastern Greenland, Norway, and the coast of western Europe. The U.K. Met Office recently issued a report on the December and January storms that ravaged the British coast, saying
, "For England and Wales this was one of, if not the most, exceptional (two month) periods of winter rainfall in at least 248 years." No studies have confirmed a link between these intense winter storms and climate change, but some scientists think climate-driven changes in the jet stream
may be behind the wild weather.
07 Mar 2014:
U.S. Car-Sharing Programs Have
Taken 500,000 Cars off Roads, Report Says
The rapid growth of car-sharing programs has cut the number of vehicles on U.S. roads by more than half a million, according to new research
by AlixPartners, a consultancy group with clients in the automotive industry. The trend will continue beyond 2020, the group projects, at which point 4 million people will be participating in car-sharing programs and 1.2 million fewer cars will be on the road. Of the 10 cities surveyed, residents of Boston, home of the Zipcar company, were most aware of car-sharing programs. Young people and, surprisingly, households with children were least likely to own their own cars, the survey said. Roughly half of the people who had tried car-sharing had already decided not to purchase or lease their own car, and did not plan to do so in the future. Rather than environmental concerns, nearly 60 percent of interviewees said cost and convenience led them to participate in car-sharing.
06 Mar 2014:
Warm River Water Plays Major
Role in Arctic Sea Ice Melt, Study Finds
Relatively warm water flowing into the Arctic Ocean from rivers contributes significantly to Arctic sea ice melt each summer, a phenomenon that will intensify as the region warms, according to NASA researchers
. The river discharge not only melts coastal sea ice, it also has
a wider climate impact as it creates more open water, which is darker than ice and absorbs more heat from sunlight. As these NASA images show, when water from Canada's Mackenzie River flowed into the Beaufort Sea in the summer of 2012, average surface temperature of the open water rose by 6.5 degrees C (11.7 degrees F) after the pulse of river water. Flow from the Mackenzie raised sea surface temperatures as far as 350 kilometers (217 miles) from the coast. The researchers note that river discharge is becoming an increasingly important contributor to melting Arctic sea ice because the volume and temperature of fresh water discharge is increasing as inland Arctic areas warm more each summer.
03 Mar 2014:
Harsh Winter Causing Large
Die-off of Invasive Insects, Researchers Say
As a frigid winter takes a toll on the United States and Canada, invasive insect populations are also taking a hit. The U.S. Forest Service estimates that up to 80 percent
of emerald ash borers, which have been decimating ash tree populations, were killed by long
Emerald ash borer
stretches of bitter cold in the the upper Midwest this year. Several other insect pests, many of which have migrated northward because of milder winters in recent years, also are faring poorly this winter, including corn earworms and gypsy moths. Researchers remain skeptical, however, that the die-offs will have lasting effects on pest populations. Emerald ash borers in Chicago, for example, survived the sub-zero weather because Chicago temperatures fell only to -17 degrees F, rather than Minnesota's -20 degrees F, which seems to be a critical temperature threshold for the pests.
27 Feb 2014:
Pine Forest Aerosols Play
Significant Role in Climate, Study Says
Pine forest vapors form small aerosol particles that may significantly cool the climate by reflecting the sun's energy back into space, according to new findings
. Scientists have known for decades that gases from pine
Hyytiälä pine forest in Finland
trees can form particles that grow from just 1 nanometer in diameter to 100 nanometers in about a day. The new research, published in Nature
, shows the rapid growth of these particles relies on a chemical chain reaction among pine-scented molecules and atmospheric ozone and oxygen. The growing particle then grabs others like it, eventually snowballing into a 100-nanometer particle — one that's large enough to condense water vapor, prompt cloud formation, and, ultimately, influence climate. Boreal or pine forests give off the largest amount of these compounds, so the finding is especially relevant for the northern parts of North America, Europe, and Russia. But other types of forests emit similar vapors, and the scientists think these may undergo similar rapid chemical reactions.
26 Feb 2014:
Large Offshore Wind Farms
Could Soften Blow of Hurricanes, Study Says
Offshore wind farms with thousands of wind turbines could have sapped much of the power of hurricanes Sandy, Katrina, and Isaac, significantly slowing their wind speeds, decreasing their accompanying storm surges, and possibly preventing billions of dollars in damages, according to a new study
. Computer models
used in the study said that deploying tens of thousands of offshore wind turbines could absorb enough energy from a hurricane to reduce peak wind speeds by 56 to 92 mph and storm surges by 6 to 79 percent. "We found that when wind turbines are present, they slow down the outer rotation winds of a hurricane," said Stanford engineer Mark Jacobson, who led the research. "This feeds back to decrease wave height ... which in turn slows the winds of the entire hurricane and dissipates it faster." For Hurricane Katrina, a massive turbine array could have slowed wind speeds by 58 percent and storm surge by 79 percent, and for Sandy wind speeds could have been cut by 14 percent and storm surge by 34 percent, according to findings published in Nature Climate Change
19 Feb 2014:
Loss of Arctic Sea Ice
Has Greater Warming Impact Than Expected
The steady disappearance of Arctic sea ice, which is causing the exposed and darker surface of the Arctic Ocean to absorb more sunlight, is having a more profound impact on global warming
estimated, according to a new study. The decline of albedo, or reflectivity, from the Arctic Ocean equals roughly 25 percent of the warming caused by rising carbon dioxide levels, according to scientists at the University of California, San Diego. The impact of this "albedo feedback," in which the highly reflective white surface of sea ice is replaced by heat-absorbing open ocean, is considerably stronger than climate models had predicted, according to the UCSD research
, published in the Proceedings of the National Academy of Sciences.
Researchers had thought increasing Arctic cloud cover might slow the albedo feedback, but this study indicates that is not happening.
Five Questions for Elizabeth Kolbert
On Facing Up to the Sixth Extinction
Elizabeth Kolbert's new book, The Sixth Extinction
, focuses on one of the most troubling realities of our age:
We are living in a period when, for only the sixth time in earth’s history, the diversity of species is contracting suddenly and rapidly — but now, we humans are the cause. For her reporting, Kolbert, an e360 contributor
and New Yorker
staff writer, traveled from the Peruvian Andes to Australia's Great Barrier Reef, probing the fate of a dozen species. Yale Environment 360
asked Kolbert five questions about the book and what she discovered in researching it.
14 Feb 2014:
Climate Benefits of Natural Gas
Are Questioned in A Major New Report
The U.S. Environmental Protection Agency has been underestimating methane leaks from natural gas production and use by 25 to 75 percent, according to a comprehensive assessment
of more than 200 studies. When the methane leaks are accounted for, natural gas contributes to climate change more than industry and the EPA have claimed, concludes the report by a team of U.S. scientists. In some cases, natural gas contributes to warming more than other fossil fuel sources. For instance, fueling trucks and buses with natural gas instead of diesel likely increases emissions, because diesel engines are relatively efficient, according to the researchers. Natural gas has been touted as an important "bridge fuel" because it emits less CO2 during combustion than oil and coal. Recently, though, studies have indicated that leaks of methane, a more potent greenhouse gas than CO2, during natural gas production, transportation, and consumption may offset its climate benefits. The new report, published in Science
, synthesized the results of 20 years' worth of methane leakage studies.
12 Feb 2014:
Despite Costs, Most Americans
Want Action on Climate Change, Report Finds
A large majority of Americans — 83 percent — say the U.S. should make an effort to reduce global warming, even if those efforts have economic costs, according to a new report
from the Yale Project on Climate Change Communication. As many as 56 percent of Americans would be willing to pay an extra $100 each year if their power company would generate 20 percent of its electricity from renewable sources. Corporations and industry should be doing more to stave off climate change, according to 65 percent of people interviewed in a national survey, and 61 percent believe individual citizens should also be taking a more active role. Many of the survey's findings are similar across Democratic and Republican party lines. Tax rebates for energy-efficient vehicles and solar panels are popular among people aligned with both parties, for example, as well as funding renewable energy research and regulating carbon dioxide as a pollutant. And people from both parties are generally supportive of ending all fossil fuel subsidies, although Democrats (67 percent) are more supportive of that policy than Republicans (52 percent).
06 Feb 2014:
Maps Show Tropical Corridors
Important to Wildlife As Climate Changes
A new set of maps
highlights the importance of habitat corridors in helping wildlife deal with the effects of climate change and deforestation. The series of maps shows more than 16,000 habitat corridors
— swaths of
land that connect forests or protected areas and allow animals to move between them — in tropical regions of Africa, Southeast Asia, and South America. High-resolution data on biodiversity, endemism, and vegetation density allowed the researchers, led by Patrick Jantz of the Woods Hole Research Center, to determine which corridors are most important for maintaining biodiversity under changing climate conditions. The maps also highlight which corridors are most important for sequestering carbon and averting carbon emissions associated with deforestation. Researchers hope the findings will help guide wildlife protection plans and serve as a framework prioritizing the conservation of habitat corridors.
05 Feb 2014:
Vast Forests and Frequent
Fires Were Key Causes of Ancient Warming
The release of volatile organic compounds from forests and smoke from wildfires had a far greater impact on global warming 3 million years ago than ancient atmospheric levels of carbon dioxide, a new study finds
. During the mid-Pliocene epoch, forests covered a much larger percentage of the planet, releasing large amounts of volatile organic compounds, according to Nadine Unger of the Yale School of Forestry & Environmental Studies. Those compounds are precursors to ozone and organic aerosols, which are both potent greenhouse gases. The dark foliage of the planet's abundant forests also absorbed large amounts of solar energy, another reason why the Pliocene was a relatively warm era even though atmospheric levels of CO2 were not exceptionally high. The research — based on earth-system modeling that used a supercomputer capable of processing 52 trillion calculations per second — provides evidence that dynamic atmospheric chemistry played an important role in past warm climates, underscoring the complexity of climate change, the authors write in Geophysical Research Letters
04 Feb 2014:
NASA Image of Alaska
Depicts Spring-like Temperatures and Thaw
As the continental U.S. faced frigid weather and major winter storms in January, Alaska experienced record high temperatures.
A map based on NASA satellite data
shows that the last half of January was one of the warmest winter periods in Alaska’s history, with temperatures as much as 40 degrees F (22 C) above normal on some days in the central and western portions of the state. A high pressure system off the state's western coast sent warm air and rain through Alaska instead of down into California, which is in the midst of a record drought. The warmest January temperature ever observed in Alaska was tied on January 27, when the thermometer hit 62 F (16.7 C) at Port Alsworth, in southern Alaska. Combined with rainstorms, the heatwave set off a host of spring-like effects, including avalanches and swollen rivers, which carried major sediment loads into the Gulf of Alaska. Inland, Arctic lakes are also seeing consequences of Alaska's long-term warming trend. A new study
found that lakes in the region froze almost six days later and broke up about 18 days earlier in the winter of 2011 compared to the winter of 1950.
03 Feb 2014:
Greenland's Jakobshavn Glacier
Is Moving at Record Speeds, Study Finds
Greenland's Jakobshavn Glacier is flowing into the ocean at a record pace of more than 17 kilometers per year, according to research
by U.S. and German scientists. The glacier, which drains 6 percent of the
massive Greenland ice sheet, moved at a rate of 46 meters per day in the summer of 2012 — four times the glacier's 1990s summer pace. The unprecedented speed appears to be the fastest ever recorded for any glacier or ice stream in Greenland or Antarctica, the researchers report in the journal The Cryosphere
. Scientists estimate the glacier added about 1 millimeter to global sea levels from 2000 to 2010; its faster flow into the ocean means Jakobshavn will add even more water over the current decade. Widely thought to be the source of the iceberg that sunk the Titanic
in 1912, the researchers say Jakobshavn is flowing at record speeds because its front edge, called the calving front, now overlies a particularly deep spot on the ocean floor. "As the glacier’s calving front retreats into deeper regions, it loses ... the ice in front that is holding back the flow, causing it to speed up," the lead researcher explained.
31 Jan 2014:
U.S. State Department Report
Boosts Prospects of Keystone XL Pipeline
In a long-awaited report, the U.S. State Department has concluded that the carbon-heavy oil from Alberta's tar sands will be extracted whether or not the Keystone XL pipeline is built, improving the prospects
that the highly controversial project will be built. In an environmental impact statement
that was six years in the making, the State Department concludes that the process of extracting and burning tar sands oil creates 17 percent more greenhouse gases than traditional oil, but that the heavily polluting oil will be brought to market with or without the pipeline. "It's unlikely for one pipeline to change the overall development of the oil sands," said a State Department official. If completed, the pipeline would carry 830,000 barrels of oil a day from Alberta to refineries on the coast of the Gulf of Mexico. President Obama will make the final decision on the Keystone XL pipeline and he vowed last year that he would approve the pipeline only if it would not "significantly exacerbate" the problem of carbon emissions. Environmental activists such as Bill McKibben of 350.org have said it would be "game over" for the climate if Keystone XL is built.
30 Jan 2014:
NASA Animation Shows
Relentless Pace of Warming Since 1950
A 15-second NASA animation
shows the steady and rapid warming of the planet since the middle of the 20th century, with regions in the Arctic and Siberia warming as much as 2 to 4 degrees C (3.6 to 7. 2 degrees
F) above a long-term average. The animation begins in 1950, but the intensity of the yellow, orange, and red colors shows how much temperatures have increased compared to baseline temperature data collected from 1880 to the present. NASA said that nine of the planet's 10 warmest years have occurred since 2000, and worldwide surface temperatures continued to rise in 2013
, according to satellite and meteorological data. Since 1880, when atmospheric concentrations of CO2 were 285 parts per million (ppm), the average global temperature has risen 1.4 degrees F; atmospheric CO2 concentrations crossed a milestone of 400 ppm last year. "Long-term trends in surface temperatures are unusual and 2013 adds to the evidence for ongoing climate change," NASA scientist Gavin Schmidt said.