Two months ago, NASA's Timothy Hall and colleagues published a study that described how they had estimated the amount of manmade carbon dioxide absorbed by the ocean since the start of the industrial era.

Oceans absorb about a third of the carbon dioxide that humans release into the atmosphere, so sorting out a long-term record of carbon uptake is of great interest to climate scientists.

To create their record of the ocean's uptake of carbon, Hall and Samar Khatiwala, the lead author of the study, devised a clever mathematical technique that proved to be a considerable advance. When Hall's study appeared in the journal Nature, he assumed the creation of this new long-term, continuous record would headline the news.

But journalists gravitated toward something else entirely: a brief mention that the amount of carbon dioxide absorbed by the ocean seemed to be experiencing, as the researchers put it, "a small decline in the rate of increase in the last few decades."

"Seas Grow Less Effective at Absorbing Emissions", one headline trumpeted. Another article compared the world's oceans to a fish "stuffed to the gills" with carbon dioxide and another reported a "sudden and dramatic drop in the amount of carbon dioxide being absorbed by the sea."

Given the caveats included in the original study, all of this caught Hall slightly off guard. I'll let Hall, who summarized his reactions to the coverage for What On Earth, pick the story up from here:

My coauthors and I had viewed the ability to estimate the history of ocean uptake of anthropogenic carbon as the highlight of the paper. Previously, observationally-based estimates had only provided a few snapshots in time, and we were proud of the cleverness of our techniques.

It seems clever mathematical techniques, however, don’t make good press releases. Interestingly, coverage of the paper has not focused on the fact that we can estimate the uptake history. Instead it has focused on apparent reductions in the rate of uptake over the last 2 decades.

The figure below shows our estimate of ocean uptake since 1775. The first impression is the rapid increase since 1950, coinciding with the rapid rise in carbon emissions to the atmosphere. The oceans have prevented about 1/3 of anthropogenic carbon emissions from accumulating in the atmosphere. A closer reading of the curve reveals a reduction in the uptake’s rate of increase after about 1980, even while emissions continue to increase.

Scientists have long suspected that ocean carbon uptake would eventually be unable to keep pace with rising emissions. Basic aqueous chemistry tells us that, as dissolved carbon in seawater increases, seawater becomes less able to absorb new carbon. Eventually, the absorption saturates. The slowing down of the increase rate may be an early signal of this saturation.

However, recent changes in uptake were not our focus when we performed the study, and more importantly we did not analyze the statistical significance of the slowdown. We plan further analysis on these trend variations. What we can say is that there are physical reasons to suspect a reduction in the ocean’s capacity to keep pace with increasing carbon emissions, and that there are now strong observational hints for recent reductions.

Hall advises reading this story, which also appeared in Nature. It's less dramatic and more technical than most of media accounts, but it is a more accurate representation of the paper.

--Adam Voiland, NASA's Earth Science News Team
   Image Credit: (EPOD/K. Chrisodoulopoulus)

An early morning sun illuminated the light rain over Nevada, Missouri, on May 14, 2009, spraying rays across the sky. Photographer Tommy Hornbeck captured what some viewers may believe to be virga, rain that evaporates before reaching the surface. However, Jim Foster, a hydrologist at NASA’s Goddard Space Flight Center, confirmed with Hornbeck that the rain did indeed dampen the ground and the photographer below. 

Stanley Morain is not an asthmatic. But like a lot of other healthy people, his lungs are sensitive to dust in the air in his hometown of Albuquerque. Dust makes him cough. It makes his eyes tear. It makes him pretty miserable.

Morain believed that if he -- a healthy individual -- is affected by the dust storms common to the American southwest, then hundreds of thousands of asthmatics must be affected far more severely when millions of tiny particles nestle into their respiratory systems.

His career has led him to a spot as director of the Earth Data Analysis Center at the University of New Mexico, where he has encouraged his colleagues and students to follow their hearts in the projects they pursue. He’s set the example by spending 10 years using NASA satellite data to create daily dust forecasts to improve health alerts.

I caught up with Morain a few days before he left for the American Meteorological Society’s annual meeting, where he gave a talk Tuesday about his work. He’s especially excited about decisions by the United Nations and the Joint Board of Geospatial Information Societies to publish his latest dust modeling work this spring.

WhatOnEarth: How did you decide to focus your career on using satellite sensors to improve public health?

Morain: The thought first struck me years ago, before I got my doctorate in biogeography and before I was awarded my first NASA research grant in 1964. I’ve always been fascinated by the geographic aspects of health even when I worked on NASA projects as dissimilar as lunar landers in the 1960s. I found we could combine information technology and modeling to learn more about health problems like heart attacks, Valley Fever, and hantavirus pulmonary syndrome that frequently strikes and kills young, otherwise healthy people within 24 hours.

WhatOnEarth: The Centers for Disease Control estimate 16.4 million adults and 7 million children in the U.S. suffer from asthma. How do your dust alerts help them?

Morain: Well, we’re not yet operational on a large-scale basis. That would take a commercial firm stepping in to make our alerts available nationwide. But, in my own backyard, the alerts are helping asthmatics plan for the worst days. Dust is a real problem here. When people know dust is headed their way, they can adapt their plans to minimize time outdoors or increase the dosage of some asthma medications. We’re making the alerts available, by way of summaries of dust and air quality conditions, to everyone from school nurses to TV news broadcasters to epidemiologists who are concerned about how long-term dust exposure affects the overall population.

WhatOnEarth: How do NASA satellites play into the development of the alerts?

Morain: There are environmental triggers for diseases like asthma. Very fine pollutant particles called aerosols are key examples of such triggers. NASA satellites like Terra and Aqua have instruments that can “see” the path dust takes. When you merge dust modeling information from the satellites with the National Weather Service weather forecasting model, you get a product that tells you when a weather event will bring dust along with it. The product becomes the basis for our daily dust alerts.

Three generations of model improvements for a dust storm across New Mexico and Texas on 15-16 December, 2003 illustrate (left) model performance before and (middle) after satellite data were included; and (right) the same storm modeled by the higher resolution, weather forecasting model Morain’s team uses. Credit: Morain/Earth Data Analysis Center

-- Gretchen Cook-Anderson, NASA's Earth Science News Team

Field assistants tromped through bogs in Harriman, NY to collect sediment cores that NASA

scientist Dorothy Peteet is using to date the retreat of the Laurentide Ice Sheet.  Credit: Peteet

I spent big chunks of my childhood mucking through the lakes and bogs of New England with my brothers and looking for any number of critters hidden in the silt.

Turtles, of course, were the main draw (minus the snappers, which we knew were capable of mangling a toe or finger with a passing chomp), but actually snagging one always was a rare treat. Bullfrogs, salamanders, and newts were our standard catch.

If only we’d had a microscope. Watching Goddard Institute for Space Studies (GISS) botanist Dorothy Peteet show images of tiny fragments of pollen, seeds, and fossils that settled to lake bottoms and sat largely unchanged for thousands of years reminded me of the extraordinary oddness--and beauty--that’s lurking in the most unsuspecting of places.

Look, for example, at this fossilized head shield of a daphnia, or water flea, which Peteet showed during presentations at GISS and the American Geophysical Union meeting last December. It’s a miniscule planktonic crustacean with a transparent body and a heart that beats visibly:

Or this statoblast, a peculiar little reproductive pod that can withstand desiccation and freezing and buds from aquatic creatures called bryozoans:

Or this one, a fossilized leaf of a fruit-bearing, cold-loving tundra plant, perhaps a blueberry:

 

Peteet isn't poking around in the mud just for fun like my brothers and I did as kids, though. She’s collecting bog cores and scrutinizing the bits of fossilized plants and animals, which can be dated quite precisely using radiocarbon techniques, that turn up in the cores. Her goal is to pinpoint the timing of the collapse of the Laurentide Ice Sheet, a massive block of ice that stretched as far as Long Island during the peak of the last ice age. With Arctic ice currently undergoing rapid retreat, sorting out how the Laurentide Ice Sheet collapsed has big implications for understanding how climate change might proceed.

By analyzing material from some of the first creatures to colonize glacial lakes after the ice retreated, such as those water fleas, Peetet can estimate the date the ice sheet collapsed. Her findings suggests that the collapse occurred about 15,000 years ago, which would put it five-to-ten thousand years later than other dating techniques (particularly one influential technique that involves dating the beryllium from boulders dropped by the retreating ice sheet). 

"This was surprising, and it's generated some controversy," she told her colleagues. "I'd like to have your ideas about what's going on." To learn more about the topic, you can watch, listen, or view a pdf of Peetet's full presentation here. 

Share your stories about exploring the muck in your neighborhood, your ideas on the dating controversy, and we'll make sure that Peteet sees them and posts a reply.

Botanist Dorothy Peteet

                                                                                                                                                                 
--Adam Voiland, NASA's Earth Science News Team       

Our friends at NASA's Global Climate Change site have a great blog post today that we'd like to share. The message is simple yet critical: rising sea levels do not and will not mean the same thing everywhere on the planet. Oceanographer Josh Willis of the Jet Propulsion Laboratory puts it this way:

Even though it’s sometimes convenient to think of the ocean as a great big bathtub, where turning on the tap at one end raises the water level in the whole tub, real sea level rise doesn’t quite happen that way. To understand why, you first have to realize that ‘sea level’ isn’t really level at all.

There are lots of reasons why the oceans are not level. For example, vast ocean currents like the Gulf Stream in the Atlantic Ocean and the Kuroshio in the Pacific actually reshape the ocean surface, causing it to tilt. As the planet heats up, changes in the prevailing winds (which drive most of these ocean currents) cause changes in the currents, reshaping our ocean and changing local sea level as a result.

Just as global warming does not raise land temperatures evenly, global ocean warming is not the same everywhere around the globe. Some regions of the oceans are heating up faster than others, and because warm water takes up more space than cold water, those regions experience faster sea level rise.

Finally, the water locked away in the great ice sheets of Greenland and Antarctica also shapes the ocean surface. As the ice sheets melt and lose water to the oceans, our entire planet feels the effects. The movement of mass from the ice sheets to the oceans very slightly shifts the direction of Earth’s rotation. This, along with changes in the gravitational pull of the ice sheets on the oceans, will reshape sea levels further still...

Click here to read the full posting from Josh. And be sure to check out the interactive sea level rise viewer. 

-- Mike Carlowicz, Earth Science News Team

CO2 is released from fires (red dots) like these near Lake Malawi in southern
Africa in October 2009 for agricultural land clearing. Credit: NASA 

Deforestation. The environmental implications of the word are as numerous as the syllables. And scientists like Jim Collatz have the job of trying to ferret out and prove those implications. Or, as the case may be, of correcting what scientists have believed to be true.

When farmers or loggers chop or burn forest land, they set in motion the loss of biodiversity and habitat, as well as soil erosion. Collatz and other scientists are just as concerned -- maybe even more so – with the carbon dioxide (CO₂) deforested areas contribute to the atmosphere, warming the climate.

Click here for a multimedia presentation of Richard Alley's AGU talk.  (Credit: AGU)

Scientists aren't known for being the savviest of public speakers, but Penn State's Richard Alley is that rare researcher who knows how to give a talk. Alley -- who's willing to sing, dance, and gesticulate vigorously to get a point across -- gave a lecture about carbon dioxide to an overflow crowd of scientists at the American Geophysical Union meeting this year that's well worth watching.

Blogger and University of Toronto computer scientist Steve Easterbrook has an excellent blow-by-blow of the talk, but the heart of it came down to this point, which Alley made on his last slide:

An increasing body of science indicates that CO2 has been the most important controller of Earth's climate. 

If you want the details, (and the details are a pleasure to sit through in this case because of Alley's gregarious speaking style) AGU has posted video and slides of the full talk. Still want to know more about carbon dioxide? NASA's Jet Propulsion Laboratory (JPL) released new details about the distribution of carbon dioxide in the troposphere, the region of Earth's atmosphere that is located between 5 to 12 kilometers, or 3 to 7 miles, above Earth's surface. (JPL also released a ten question quiz about the gas that you can access here).  

Meanwhile, Alley participated in a NASA science update back in 2005 that explored the nature of sea level rise, a topic that NASA researchers continue to investigate and that you can explore interactively using our Sea Level Viewer.

--Adam Voiland, NASA's Earth Science News Team

There’s a staggering amount of science presented every year at the American Geophysical Union meeting, Earth science’s equivalent of the post-season, prom, and a college reunion all rolled into one. This year, with more than 16,000 attendees and 15,815 abstracts on the docket, was no exception.

AGU groups all the abstracts into one of 27 categories. Hydrology garnered the most attention from scientists (12.2 percent of all abstracts) followed closely by Atmospheric Sciences (11.1 percent) and finally Volcanology, Geochemistry, and Petrology (8.0 percent). The full breakdown is below:

NASA, though best known for sending men to the moon and robots to Mars, had plenty of Earth science -- including stories about black carbon, California’s carbon budget (and dwindling water supplies), greenhouse gases, and one of our Earth observing flagships -- to add to the mix as well.

--Adam Voiland, NASA's Earth Science News Team