May 24, 2010, 17:00 PDT

Man vs. wild

The environment or climate change?

Tony Freeman

By Dr. Tony Freeman, Earth Science Manager, NASA Jet Propulsion Laboratory

Recent coverage of the oil spill in the Gulf of Mexico reminds us how vulnerable some ecosystems are to environmental disasters, whether natural or caused by mankind. The pictures of seabirds and marine mammals covered in crude oil are distressing to most of us. There’s also going to be an impact on our economy because of the cost of cleaning up the mess. It’s obvious, though, that this is an environmental problem not related to climate change. It’s also a problem that may take decades to clean up, but whose effects will be local, not global.

The Gulf oil slick is visible as a bright diagonal swath in this image taken at 28,000 feet from a camera mounted on a B-200 research airplane from NASA's Langley Research Center. Credit: NASA.
The Gulf oil slick is visible as a bright diagonal swath in this image taken at 28,000 feet from a camera mounted on a B-200 research airplane from NASA's Langley Research Center. Credit: NASA.

Across the Atlantic, there’s an environmental problem caused by nature — the ash cloud from the Icelandic volcano, Eyjafjallajokul, which has been grounding flights out of Europe. Here the economic costs are lost revenues for the airlines, but there’s unlikely to be any harmful impact on ecosystems. Volcanic eruptions have had long-term effects on Earth’s climate in the past, the most recent being Mt. Pinatubo in 1991, the second largest volcanic eruption of the 20th century, which ejected 100 times more ash into the upper atmosphere than Eyjafjallajokul will. Mt. Pinatubo’s ash reduced the amount of sunlight reaching the Earth’s surface, cooling the Earth’s atmosphere a little. The current Icelandic eruption is unlikely to have the same effect, according to scientists (Ashley Davies, JPL, private communication).

For events like the Station fire that destroyed much of the chaparral (dense vegetation) on the San Gabriel mountains near my home, it can be a little harder to say whether it’s a climate change- or environment-related event. On the one hand, climate models predict that wildfires will become more common as temperatures increase; on the other, these areas tend to burn every 30 years or so anyway. And then there’s always the chance that the cause of a given fire may be arson.

It can be difficult to separate natural and man-made disturbances of the environment from natural and man-made disturbances of the climate. Tree logging has an effect on the environment through destruction of forest habitat, but on a large enough scale, it can affect climate by reducing the amount of carbon dioxide (CO2) absorbed by forests. Elevated levels of CO2 in Earth’s atmosphere trap heat, raising the Earth’s temperature, as we see from satellite measurements of the land, ocean surface and atmosphere. Higher temperatures can have environmental effects: drought conditions in some areas, higher rainfall in others, for example. So some environmental problems are linked to climate change, but some are not. Differentiating between them helps clarify our discussions of climate change, its causes and what to do about it.

May 19, 2010, 17:00 PDT

Pick of the pics

Star of the show

SDO image

This image shows one of the first pictures from NASA's recently launched Solar Dynamics Observatory, or SDO. The spacecraft is revealing never-before-seen details of material streaming outward and away from sunspots. Other images offer extreme close-ups of activity on the sun’s surface, and the first high-resolution measurements of solar flares in a broad range of extreme ultraviolet wavelengths. The sun's activities affect everything on Earth, and SDO should offer unprecedented insights into our star's dynamic processes. For more information, take a look here.

May 10, 2010, 17:00 PDT

Pick of the pics

Can't pronounce its name, but can see it from space

Credit: NASA Goddard / MODIS Rapid Response Team.

Credit: NASA Goddard / MODIS Rapid Response Team.

After more than a week of relatively subdued activity in late April 2010, Iceland’s Eyjafjallajokull Volcano began a fresh round of explosive ash eruptions in the first week of May. On May 10, 2010, the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard NASA’s Aqua satellite captured this view of a thick plume of ash blowing east and then south from the volcano (top left). The ash plume can be seen streaming in a straighter, more steady path than the day before, indicating winds were stronger than they were on May 9. Farther south in the image the ash plume has become partially obscured by higher clouds (white). By May 10, the ash had reached North Africa, Turkey and Morocco.

Caption courtesy of NASA's Earth Portal.