Climate change chronicles from NASA

By Dr. Josh Willis, Oceanographer, NASA Jet Propulsion Laboratory

Don’t you just love a good disaster movie? I remember when I saw "The Day After Tomorrow" in the theater; I actually thought it was pretty cool. Of course, a lot of my nerdy scientist friends complained that it was inaccurate and that it blew climate change all out of proportion. It did, of course.

But I thought it was pretty neat to see a Hollywood disaster movie where the disaster was caused by the disruption of a well-known, real-life set of ocean currents called the “Ocean Conveyor Belt.” Well, okay, we scientists call it the “Atlantic Meridional Overturning Circulation,” but I give Hollywood points for doing a bit of homework.

In the movie, our hero Dennis Quaid notices that all the ice in Greenland is about to melt and run into the Atlantic Ocean. He (rightly) notes that such an event would slow down or stop the Ocean Conveyor Belt, and then predicts that it will wreak havoc on the global climate.

Of course, the movie vastly exaggerates the importance of the Conveyor Belt and the speed with which any changes might occur, but it turns out that the basic idea was based on actual research. Climate scientists who study the most recent ice age have suggested that the Ocean Conveyor Belt might have played a role in rapid cooling events that occurred tens of thousands of years ago throughout the last ice age.

Today’s climate is much warmer, and the effect of the Conveyor Belt is probably not as dramatic as it was back then. But global warming is predicted to slow down the Conveyor Belt in the coming decades. If it does, then patterns of rainfall, drought and even hurricane activity in the Atlantic could be affected.

That’s why oceanographers have been scrambling to figure out how best to measure this thing we call the Conveyor Belt. You can imagine then, how excited I was when I figured out that I could see changes in the Conveyor Belt using data from ocean satellites and floats. So far, it looks like the predicted slowing hasn’t started yet.

That’s probably not too surprising, as the oceans are slow to respond to global climate change. But it’s still pretty neat to imagine how the oceans could play such an important role in Earth’s climate. Not only do they absorb most of the extra heat from global warming, they might also play a role in shifting rainfall patterns and fueling storms. That’s one of the reasons I liked "The Day After Tomorrow." Even though it was unrealistic, the movie reminds us that the ocean is the Big Kahuna when it comes to global warming. Just ask Dennis Quaid.

From Dr. Tony Freeman, NASA's Jet Propulsion Laboratory

Searching for vacation ideas recently on the web, I came across a recommendation by the intrepid “Man vs. Wild” TV survival expert, Bear Grylls. His tip referred to a tour company offering a cruise of the Northwest Passage — a sea route in the Arctic Ocean that connects the North Atlantic to the North Pacific Ocean. The tour covers over 2500 miles (4000 kilometers) from Resolute in Nunavut, Canada (which is also known as the “place with no dawn”), to Cambridge Bay in Nunavut. The fact that such tours exist brought home to me both the rapidity of climate change in the Arctic, and a perhaps unanticipated benefit.

Growing up in the second half of the twentieth century, the Northwest Passage was to me the stuff of fable and legend, straight from the great age of exploration. Such a passage would connect Europe to Asia via a shorter route and avoid the long journey south around Africa. For centuries, the passage has been sought by explorers as a possible trade route. Unsuccessful attempts were made by several famous figures including Sir Francis Drake, John Cabot, Sieur de La Salle, Jacques Cartier and, a great hero of mine, Captain Cook. In 1845 Sir John Franklin’s famous expedition to find the Northwest Passage floundered in the ice, with all hands lost to starvation, exposure and perhaps worse. Norwegian explorer Roald Amundsen was more fortunate, and in 1906 he completed the first successful navigation of the Northwest Passage, but only by taking a route south of Victoria Island. His journey was fraught with danger — it took three years in a converted herring boat, with winters spent trapped in the ice waiting for the frozen sea around them to thaw.

Captain Roald Amundsen leaving home for the North Pole, 1920.

The Arctic as observed on August 5, 2008, by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) onboard NASA’s Aqua satellite. Blue indicates open water, white indicates high sea ice concentration and turquoise represents loosely packed sea ice. The black circle at the North Pole indicates no data as the satellite does not make observations directly over the pole. Image credit: NASA/Jesse Allen, using data obtained courtesy of the National Snow and Ice Data Center (NSIDC). Image from here.

In the summer of 2007, Arctic sea ice reached a record low and the fabled passage saw enough ice melt to make navigation feasible. The global significance of this opening, which is clearly visible in NASA’s satellite data, is that it represents a shorter trade route for ships traveling between the Northern Pacific and Northern Europe in comparison to the Panama Canal route, and could make large-scale Arctic shipping possible. But to me, declaring the Northwest Passage open for tourism is like announcing day trips to Eldorado, or submarine cruises to Atlantis, or charter flights to Shangri-La.

Annual Arctic sea ice minimum extent as seen from space. ‘Sea ice minimum extent’ refers to the smallest amount of ice coverage in the Arctic, which occurs each year during the Arctic summer when temperatures are highest. Courtesy of Waleed Abdalati, University of Colorado.

Tony Freeman is an Earth science manager at JPL.

Credit: NASA ASTER satellite.

In this 2002 image, soaring, snow-capped peaks and ridges of the eastern Himalayas create an irregular white-on-red patchwork between major rivers in southwestern China. The Himalayas are made up of three parallel mountain ranges that together extend for more than 2900 kilometers (1800 miles).

Courtesy of the extremely cool NASA/USGS Earth as Art gallery.

From Mike Carlowicz, NASA's Earth Science News Team

Oceanographer Josh Willis of NASA's Jet Propulsion Laboratory was recently honored by the White House as a recipient of the Presidential Early Career Award for Scientists and Engineers (PECASE). Willis studies the ocean — particularly the height of the sea surface — with satellite data, though he also works with colleagues who put instruments below the surface of the water. By blending such measurements, he has already made a scientific mark in the study of sea level rise. We caught up with Josh — shown above with White House science advisor John Holdren and NASA deputy administrator Lori Garver — to discuss his inspiration, the importance of the ocean, and the necessity of communicating science.

When you were a child, what did you want to be when you grew up? When did you decide you wanted to be an ocean scientist? When I was 9 or 10, I found a book about Einstein's Theory of Relativity that my parents had lying around the house. I remember reading it and then peppering my parents with questions they couldn't answer. (This was long before Google, mind you.) So for a long time, I wanted to be a physicist. A couple years of graduate school in physics convinced me otherwise, and I started studying oceanography at the Scripps Institution of Oceanography. Studying the ocean and climate appealed to me because I got to use all the physics and math I learned, but it was also closer to home and of practical importance to a lot of people. Plus, it's just fun to say "oceanographer" whenever people ask me what I do.

What is the best scientific paper you have written? It's tough to say. Sometimes the papers I think are important are different from the ones that other scientists remember best. But my papers on the causes of sea level rise — based on comparisons between satellite altimeter data, observations of ocean temperature changes, and changes in ocean mass measured by the GRACE satellite — were interesting and fun to write.

What is the most important thing that few people know about the ocean? The ocean is the silent martyr of global warming. We always think of global climate change in terms of the warming atmosphere, but it is actually the ocean that absorbs almost all of the extra heat and a whole lot of carbon dioxide [CO2]. The warming contributes to sea level rise and changes ocean ecosystems, while the extra CO2 makes the ocean more acidic, threatening plankton and other tiny critters that make up the foundation of the oceanic food chain.

Why do you feel compelled to talk to the public about your science? Communicating our work is a really important part of doing science that most scientists sort of neglect. Figuring out new things about the world around us is only helpful if we communicate them to everyday people. Plus it's fun and exciting to talk to non-scientists because the questions are often interesting, and I come away feeling inspired and invigorated.

What is the funniest or strangest question you've ever gotten? I often get a chuckle out of the people who say that global warming is a vast conspiracy among scientists. Scientists love to prove each other wrong, and most of the time we can barely agree on simple questions like "Why is the sky blue?" much less orchestrate a conspiracy.

Is the PECASE award an affirmation or an inspiration for your career? This is definitely a great honor and inspiration. When President Obama met us, one of the first things he told us was how nice it was to honor a group of scientists still in the early stages of our careers. "All of you folks are younger than me!" he said. But he also made it clear that he expected a lot from us in the future. That's a pretty big inspiration when the President tells you he's expecting great things. And it's a pretty big responsibility, too. I guess that means it's probably time to get back to work now...

Cross posted from NASA’s What on Earth blog. Mike is based at NASA’s Goddard Space Flight Center outside Washington, D.C.