Harsh snowstorms on the East Coast of the U.S. Record low temperatures in Europe. Not enough snow in Vancouver for the Winter Olympics. How do these recent short-term variations add up and where do they fit in to the bigger picture of global warming?
The recent blizzard of confusing and often conflicting commentary has left many people asking questions. Is the climate really warming? Warming faster than ever? Or perhaps just weirding out?
Since NASA scientists have been tracking global temperatures and climate change for decades, we checked in with researchers from across the agency to get their take on the state of Earth's climate (which, it's worth noting, isn't the same thing as Earth's weather). The result is a collection of feature stories, videos, and cool visuals that describe what we've learned. You can find them on our new "A Warming World" page.
There you'll find:
A new video about how NASA pieces together the temperature puzzle;
An image gallery of snaps from space that show the impact of a warming world;
Why Arctic air has made this winter one to remember in many parts;
From Dr. Tony Freeman,
NASA Jet Propulsion Laboratory
Last week we learned that NASA will fly a copy of the Orbiting Carbon Observatory (OCO), after the failure to launch the first OCO in February 2009. This is great news — OCO will provide us with an unprecedented view from space of global carbon dioxide [CO2] concentrations, so we can accurately determine where this heat-trapping greenhouse gas is being put out into the atmosphere (the ‘sources’) and where it is being taken up by the oceans and by vegetation on land (the so-called ‘sinks’).
The launch failure of OCO on February 24, 2009 was almost like losing a family member to many of the team that had worked on the project. In some cases they had invested eight years of their lives in this endeavor — they poured all their energy into making it a success only to have their hopes dashed in the wee hours of the morning of February 24, 2009, at California’s Vandenberg Air Base. The satellite failed to reach orbit when the fairing (a shell-like structure that held the satellite) on the Taurus launch vehicle failed to open. The failure to shed the extra weight of the fairing prevented the satellite from reaching its planned orbit, resulting in its destruction.
The new OCO will work in exactly the same way as the original — by measuring reflected sunlight in the near infrared band (light of wavelengths 1.5 and 2 microns to be specific). CO2 absorbs light in these wavelengths — so by comparing the strengths of the absorption lines, scientists can estimate the distribution of CO2 in Earth’s atmosphere. We use similar spectroscopy techniques to determine the make-up of distant stars — yellow carbon stars similar to our own sun have carbon in their atmospheres that absorbs the light radiated from deep within the star at certain wavelengths.
One of the questions the OCO science team will try to answer is: What happens to the all of the man-made CO2 pumped into the atmosphere through combustion of fossil fuels and burning of forests? We know that roughly half of this CO2 is taken up by vegetation, through photosynthesis for example, but scientists are not sure exactly where. Is it the tropical rainforest or the northern boreal forest that does most of the ‘mopping up’ of the CO2? This gap in our knowledge of the Earth’s CO2 budget is known as the ‘missing terrestrial sink’. So with the exciting news that NASA will refly OCO in 2013 we can say that the hunt for the missing sink is on!
Tony Freeman is Earth science manager at NASA's Jet Propulsion Laboratory in Pasadena, California.
Pedersen Glacier, Alaska. Left: 1917. Right: 2005. Credits: 1917 photo captured by Louis H. Pedersen; 2005 photo taken by Bruce F. Molnia. From the Glacier Photograph Collection, National Snow and Ice Data Center/World Data Center for Glaciology.
Robert Byrne, who was an interesting combination of author and billiards champion, once said “Everything is in a state of flux,” and he was right. Our planet is constantly changing — just think about the weather, the seasons, day and night, the tides, volcanoes, earthquakes, ice ages and periods of warming and cooling — as a result of both natural and man-made effects. Sometimes nothing tracks these changes better than a picture or two.
That’s why we’re launching a brand spanking new image gallery, called State of Flux. Each week we’ll be featuring time-lapse images of different locations on planet Earth, showing change over time periods ranging from centuries to days. The pictures come from a range of intrepid explorers: Victorian photographers, astronauts on the International Space Station and NASA satellites taking snapshots of the Earth.
We start with Pedersen Glacier in Alaska, which has retreated significantly since the beginning of the 20th century. Enjoy and be sure to check back for new and stunning images of change.
Image taken by the crew of the STS-112 International Space Station mission on October 17, 2002, with a 400mm lens. Courtesy of the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Caption adapted from the Earth Observatory.
Agricultural activities and mining occur side by side in the Republic of Kazakhstan. This scene is located in the Turgayskaya Oblast of central Kazakhstan, near the provincial capital of Arkalyk, where Russian spacecraft landings occur. To the right are large, mostly square fields that likely contain spring wheat, one of the cereal grains that grows well in the cold and dry climate. The colorful, irregular patterns seen on the left appear to be surface-mining operations where water has accumulated into small lakes. Bauxite and asbestos are the principal minerals extracted in this region.
Coral reefs are incredibly fragile. Not only are most corals brittle, but they usually need pristine, clear, warm, relatively nutrient-free waters to survive. Over the past few decades, humans have put an enormous amount of pressure on coral reef environments by altering their waters and tearing up their foundations. Through water pollution, over fishing, direct physical damage, warmer ocean waters and increased acidity of the oceans, we are in danger of rapidly sending the world’s reefs into oblivion. NASA's recent Millennium Coral Reef Mapping Project found that less than two percent of coral reefs are within areas designated to limit human activities that can harm the reefs and the sea life living in and around them.
This image, taken by the NASA/USGS Landsat-7 satellite, shows Hawaii's Pearl and Hermes Atoll, which consists of a few small, sandy islands that are contained within a lagoon and surrounded by a coral reef. The island of coral is part of the recently designated Northwestern Hawaiian Islands Marine National Monument, the largest protected marine area in the world.
The Earth is a bit like the human body; its temperature is very finely balanced, and when it gets slightly out of whack big things can happen. In the case of our home planet, gases in the atmosphere play a vital role in maintaining this delicate equilibrium, by balancing the absorption and emission of all the electromagnetic radiation (microwaves, infrared waves, ultraviolet light and visible light, for example) reaching the surface of the Earth.
As we reported recently, the Earth is getting warmer. Scientists believe the main driver behind this warming trend is rising levels of man-made greenhouse gases; these gases, which we pump out into the air, act to trap heat radiation near the surface of the Earth that would otherwise be sent back out into space. Carbon dioxide (CO2) is the Paris Hilton of greenhouse gases, and gets a lot of face time because its concentration in the atmosphere has increased relatively rapidly since the Industrial Revolution. But methane, nitrous oxide, hydrofluorocarbons (HFCs), chlorofluorocarbons (CFCs) and perfluorocarbons (PFCs) are also important agents of global warming — some of them are actually much more potent than CO2 and they stick around for hundreds to thousands of years longer. This has some scientists concerned that these B-listers could actually impact global temperatures significantly more than CO2.
In a new paper, Partha Bera and colleagues at NASA Ames Research Center and Purdue University put these gases under the microscope to find out exactly why they are such powerful heat trappers. They focus on CFCs, HFCs and PFCs — all chemicals containing the atoms fluorine or chlorine — that are used in medicine, fridges and as solvents, among other things. By probing the molecular structure of these compounds, they have found that molecules containing several fluorine atoms are especially strong greenhouse gases, for two reasons. First, unlike many other atmospheric molecules, they can absorb radiation that makes it through our atmosphere from space. Second, they absorb the radiation (trap the heat) very efficiently, because of the nature of the fluorine bonds inside them. (In technical terms, fluorine atoms create a larger separation of electric charge within the molecule, and this helps the molecular bonds absorb electromagnetic radiation more effectively.) HFCs and other fluorine-based gases have been called “the worst greenhouse gases you’ve never heard of.” Now we know why.
Until now, scientists had not looked in detail at the underlying physical or chemical causes that make some molecules better global warmers than others. Bera and colleagues say that their work should help improve our “understanding [of] the physical characteristics of greenhouse gases, and specifically what makes an efficient greenhouse gas on a molecular level.” They hope their findings will be used by industry to develop more environmentally-friendly materials.