Signs From Earth

Lasers Show Thinning at Edges of Big Ice Sheets

The British Antarctic Survey has been using laser beams to determine the thickness of ice in the big sheets in Greenland and Antarctica. The scientists have found that the ice is thinning quickly along the coasts. This can be seen in red in the map above.

This report was published in the journal Nature, more info and links to the paper, pictures, maps, and PR releases are here: Space Lasers Show Greenland and Antarctic Ice Sheets Aren't What They Used to Be.

Potential implications of melting from ice sheets are explored in a New York Times article on the loss of large sections of Vietnam's Mekong Delta from sea-level rise, and another in the Financial Times Sept. 23 on similar threats to Bangladesh, a low-lying delta region at the end of the Ganges River. A study in Nature Geoscience has explored the vulnerability of river deltas worldwide to sinking and sea rise.

Climate and Fire: The Blaze Last Time, and Next

Fires over southern California have burned before and will burn again. This wafting smoke over the Pacific Ocean came from 12 large fires burning in late October, 2007.  Photo: NASA Earth Observatory

Recent news reports about fires, whether in Greece or Los Angeles, have not explained their relationship to long-term climatic shifts underway. Why? Maybe the remaining reporters and editors aren't well-versed in the underlying science of climate change, or the science and environment writers have all been laid off to save money.

News stories reporting these disasters as isolated events, or caused by cigarette or lawnmowers, miss the point and do a disservice by failing to put them in context. Temperatures have been increasing in these regions, and rainfall has been declining long-term. Just as a lawnmower may be the flint, these underlying conditions provide the tinder, and explain the likelihood that as these fires have burned before, they will burn again.

These contextual links have been made for some time by scientists, but traditional news outlets apparently haven't been reading. When fires hit Athens a week or so ago, the only outlet that explicitly explained the link between fires and climate change was the new global trends reporting website GlobalPost. 

Energy Sprawl: Renewables' Achilles Heel

Corn ethanol and wind are two renewable energy sources being pursued in the United States. A research paper on "Energy Sprawl" released in August 2009 indicates that energy efficiency is as important a strategy in energy policy as pursuing land-intensive renewable energy sources like biofuels. Photo: brooklyn/flickr

A key challenge for renewable energy like biofuels, solar, and wind becomes the large amount of land needed to produce electricity and liquid fuels at large scale.

Fossil fuels coal, oil, and natural gas are energy dense because they contain concentrated ancient sunlight. Created from carbon-rich plant residues laid down millions of years ago, fossil fuels carry via those plants the energy of millions of years of sunlight densely packed into energy-rich rocks, liquid, and gas. 

On the other hand, renewables depend on current sunlight -- today’s sun and wind, this year’s growing season -- to produce their power. Consequently the energy density of renewables is much lower than fossil fuels.

Arctic Sea Ice Melt Trend Near 2007 Level

The graph below from July 28, 2009 and released today from National Snow and Ice Data Center shows Arctic Ocean ice melt trend (blue line) close to 2007 levels (green line), which were a record. 

Last year's melt was the second most severe, and on a week ago the NSIDC reported that this season's ice melt was trending slightly ahead of 2008 levels. See Signs From Earth: Global Temperature Trends for First Half 2009 and Arctic Melt Season in "High Gear."

The summer melt season runs for about another month. The graph below and a more extensive map (above) of sea ice extent and trends are updated daily at the NSIDC website. The orange line on the July 28 map above shows average extent of sea ice for the period from 1979-2000, which is also the top line on the trend graph below.

Warm Winters Threaten California Tree Crops

Cold winter fogs that chill California fruit trees are disappearing. Photo: flickr/junmon603

Cold winter temperatures that fruit and nut trees need for proper spring flowering are disappearing from California's Central Valley. These warmer winters are beginning to adversely affect tree crops like walnuts that depend on this winter "chill" to reset themselves each year.

In a study published July 22 in PLoS One, researchers from the University of California-Davis report that the number of hours of "chill" temperatures have declined about 30 percent in the Central Valley since 1950. Apples, cherries, and pears used to grow in about half the valley's orchards but now only about four percent of the valley's orchard land is cool enough in winter to support these crops.

These rising winter temperatures will force California farmers to find new tree varieties that produce crops without this "winter chill," which trees need to trigger dormancy. 

Other studies already have shown that rising temperature and heat in California are causing changes in the type of wine grapes that can be grown there. Rising temperatures are driving a variety of changes in plant and animal behavior, and these trends for the United States are the focus of Ecological Impacts of Climate Change from the National Academy of Sciences.

Where Went the Sun's Spots?

Kenneth Chang writes in The New York Times on the apparent disappearance of the sun's spots. 

This NASA picture above shows sunspots near maximum (left) on July 19, 2000, and minimum on March 18, 2009. Some think this lack of sun spots now could bode a period of lowered solar output. 

Sunspots typically wax and wane over 11-year cycles. The sun should have reached its sunspot minimum last fall, but this spring when the number of sunspots should have been on the rise, they were still largely absent.  Some sunspots returned in June and July, but have since disappeared.

"...Among some global warming skeptics, there is speculation that the Sun may be on the verge of falling into an extended slumber similar to the so-called Maunder Minimum, several sunspot-scarce decades during the 17th and 18th centuries that coincided with an extended chilly period...."

 

Climate Catastrophe? A Rational Action Approach

 

Two years ago an Oregon science teacher produced a video called "The Most Terrifying Video You'll Ever See." Greg Craven's schoolroom lecture on how to think about global warming and decide whether action against it is needed became an internet hit with over seven million viewings.

Craven has now turned the movie into a book (isn't it usually the other way around?) called "What's The Worst That Could Happen? A Rational Response to The Climate Change Debate." 

Craven uses tools of risk assessment to help us decide how to think about and approach this issue. The focus is not on what to think about global warming, but how. The graphic above is adapted from his book, and summarizes the core argument: He sees this as a choice between action and no action against something that is true or false. 

If you see global warming as false, we do nothing against it, and nothing happens, then we can "Party!" On the other hand if you see it as false, we do nothing, and all the scientific projections come to pass, then "Global Catastrophe" is our future. 

As Craven points out, taking action against global warming comes with significant costs, but is less expensive than "Global Catastrophe." This is all about making choices and living with consequences.

Greg Craven's Website: What is The Worst That Could Happen?

Anak Krakatau Erupting at Night (Updated)

From Astronomy Picture of the Day and Stromboli Online, this picture of erupting Anak Krakatau by Marco Fulle comes from a series taken June 4-8, 2009. Original caption: "The passing storm has cleared the air: Big Dipper points towards Anak Krakatau in eruption, exactly north of Palau Rakata. The pole star is almost exactly behind the volcano, but just under the horizon." 

Update: The picture below from NASA Earth Observatory was acquired July 7, 2009 and shows this same eruption from NASA's Earth Observing-1 satellite.

Secret Pictures of Arctic Ice Released

 

A large cache of secret U.S. government images showing arctic sea ice during the past decade has been released to the public after a request by the the National Research Council. The U.S. Geological Survey made these images available July 15 through the Global Fiducials Library. The library includes high-resolution satellite images of Barrow Alaska, Beaufort Sea, Canadian Arctic, Canadian Fram Strait, Chukchi Sea, and East Siberian Sea.

The imaging project began in the mid 1990s when environmental scientists teamed with the intelligence community to determine if satellites and airplanes typically used used for military intelligence could be used to gather environmental data. According to a report in Science News, the images could not be made public until a committee determined the images could be of scientific value.

Besides individual images, the library also includes several large side-by-side comparison posters showing ice loss trends at Barrow, the Beaufort Sea, Bering Glacier, and the South Cascade Glacier in Washington State. The image below shows ice conditions at Barrow, Alaska in July 2006 and 2007.

Satellites Show Arctic Ice Thinner, Younger

Trend in Winter Sea Ice Volume: This obscure graphic from NASA show several things: 1.) Top sequence: The decline in red color shows a reduction in the amount of multiyear (MY) ice covering the Arctic Ocean in winter. The size of the red area has declined significantly from 2004 to 2008. 2.) The lower chart (black line) shows an average decline of 900 sq. km. per year in total area of ice cover over the same period. Most significantly, the steep slope of the red line in the lower graph shows the rapid loss of multiyear ice cover from 2004-2008. The rising blue line shows the increasing percentage of thin seasonal ice, or ice that appears in the fall and thaws the next summer. This juvenile ice now dominates.

 

Satellites are showing that the depth and age of Arctic sea ice is in significant decline. Multiyear winter ice has declined by more than 40 percent of its previous area in just five years from 2004 to 2008. Remaining multiyear ice also has thinned significantly, losing more than 0.6 meter depth in four years. Thin seasonal ice, ice less than a year old, has replaced multiyear ice as the dominant ice type covering the Arctic Ocean.

These results were reported July 7 by scientists from NASA Jet Propulsion Lab (JPL) and the University of Washington and published in the Journal of Geophysical Research-Oceans, a publication of the American Geophysical Union (AGU.) This follows on July 6 ice loss reports for summer 2009 from the National Snow and Ice Data Center (NSIDC), and similar April reports from NSIDC showing the rise in seasonal ice cover over the Arctic Ocean.

These accelerating ice loss trends are significant in that they bode a year soon when all ice covering the Arctic Ocean melts in summertime. Some scientists have projected that the Arctic Ocean could be ice free in summer by 2015. 

Desert Dust Alters Mountain Meadows

 

More dust in Colorado mountains causes earlier spring snow melt. Photo: Center for Snow and Avalanche Studies

Following on an earlier post here on dust covering the snowpack of southwest Colorado mountains this year, a new study in the Proceedings of the National Academy of Sciences (PNAS) reveals that the increased dust cover on snow is altering the behavior of mountain plants.  

According to the study, meadow plants typically time their flowering to rising temperatures and melting of snow, but the heat-absorbing dust causes snow to melt before ground temperatures are warm enough for plant growth. 

Dust levels in the mountains have increased about five times since the mid-1800s, mostly due to human activity in the deserts nearby, the study said. The researchers say the change in timing of snowmelt could change the composition of alpine plant communities as some species decline in abundance and others increase.

Dust on Colorado Snow Looms Over Mountainfilm

 

Dust-laden snow May 19 on Rocky Mountain peaks south of Montrose, Colorado. Photo: Dennis DImick (click to enlarge.)

I've been in Colorado the past few days, participating in a symposium on food at Mountainfilm Telluride. Last year we discussed water, and energy was our focus in in 2007. Among speakers this year were writer Bill McKibben, soil scientist Jerry Glover of the Land Institute, plant geneticist Pam Ronald of UC-Davis, and Roz Naylor, who heads the food security and environment program at Stanford. A report on the forum from the Telluride Daily Planet is here: The Future of Food: Daunting but Doable.

The film Food,Inc., shown at the festival and scheduled for nationwide release in June, will get some attention here soon. Documentary filmmaker Ken Burns also premiered his elegant new 12-hour film on the National Parks at Mountainfilm. The series will air on PBS this fall.

One scene repeatedly mentioned indoors was on colorful display outdoors in the mountains above this southwest Colorado town. The snowpack, or what remains of it, looks pink. The color comes from repeated dust storms this past winter and spring. 

Red-colored dust arrived as clouds from repeated blow-ups in the red rock areas of Utah and Arizona. The dust darkens snow and increases its melt rate. Early snowmelt and runoff from the mountains reduces the amount of water available in streams later in summer for irrigation and other uses.

The impact of dust on snow has gotten some attention in the scientific community. A study two years ago by the National Snow and Ice Data Center indicated that rising temperatures across the West are increasing the likelihood that dust storms will become more frequent, shorten the snowpack season, and affect timing of runoff in rivers and soil moisture in the mountains. The water will come off the mountains earier in the spring, and mountains soils will dry up sooner in the summer.

April 3, 2009 dust storm in northeast Arizona. From NASA Earth Observatory.

References:

Hot and Cold Winter in Color

Where was winter cool and warm? NASA Earth Observatory posted this image May 9 showing land surface temperature "anomalies" (variance from normal) across the globe during the winter of 2008-2009. Winter in this case is seen as December through February. Except if you live in the southern hemisphere.

Notable warm spots are shown in red: Greenland, Antarctica, and south central South America. Argentina suffered through a significant summer drought and heatwave (below). The western United States was warmer than normal. Shown in blue: northern and eastern North America and northern Australia were cooler than normal. 

Water Shortages Threaten Food Supply

This map shows changes in river streamflow worldwide between 1948 and 2004. Bluish colors show more runoff, reddish colors show less. (Graphic courtesy of Journal of Climate, modified by UCAR.)

Several articles published recently discuss the potential impact of declining water supplies on food production as temperatures rise and rainfall declines. Agriculture uses far more freshwater than any other human endeavor, typically from 70 to 90 percent of freshwater supply. 

Irrigation water typically comes from rivers and lakes, but dependence on groundwater aquifers is increasing as surface water declines. Water tables in several places -- the Ogallala Aquifer in the U.S.,the Saudi aquifer and the China North Plain -- are all declining as groundwater pumping tries to compensate for loss or overuse of surface water in rivers and lakes.

This tight link between water supply and food supply becomes something to ponder in light of research results showing decline in runoff from several major river systems (graphic above), and a report published in April in PNAS on projected shrinkage of Colorado River water deliveries from decreased precipitation, rising temperatures, and more evaporation.

Lake Mead in March 2008 behind Hoover Dam on the Colorado River. Levels then were down about 100 feet from full pool. Levels are now at 44-year lows. Photo: Neil McIntosh/flickr

Lester Brown discusses implications in the May issue of Scientific American. He describes the potential for food supply collapse caused by falling water tables, disappearing soils, and rising temperatures. Brown says the biggest threat for disruption comes from poor countries with fragile or non-existent infrastructure and governments.

These reports follow on a paper published in Science earlier this year detailing projected declines in food production across large areas of the sub-tropical and tropical regions because of heat waves and drought.

That paper by Battisti and Naylor projected that hot summers and declining crop yields will become common over a broad area where nearly half of the world's population lives. Most of the farmers in this region are subsistence farmers and incomes of less than $2 a day. They largely depend on rainfall for growing crops and do not have the capital, technology, or know-how to store water and irrigate.

References:

Moving Geoengineering From the Shadows

 Mount Pinatubo's 1991 eruption in the Phillippines injected sulfates into the atmosphere and cooled the earth. One geoengineering scheme would potentially replicate the cooling effects of volcanic eruptions. Photo: D. Harlow, USGS.

Would massive crop failures from heat waves and drought in the grain-growing regions of the American midwest be a sufficient reason to intentionally manipulate the atmosphere and cool the earth?

That was the opening question posed by Ken Caldeira of the Carnegie Institution and Stanford during a recent panel discussion on geoengineering at the Aspen Environment Forum. (Disclosure: I helped organize the session and event.)

This question of "geoengineering" -- whether, when, and how to intentionally change earth's atmosphere -- is poised for more attention as the carbon pollution we unintentionally produce by burning coal and oil keeps rising. As atmospheric carbon dioxide levels rise, they trap more of the sun's reflected radiant energy near the earth and drive up land and ocean temperatures.

And as temperatures go up, droughts already seen in Australia's Murray-Darling basin, or heatwaves that hit Europe in 2003 likely will become the norm, according to scientists such as David Battisti and Rosamond Naylor. Their study published in SCIENCE this year examines the likelihood and potential impact of future heatwaves on food supply as carbon emissions and temperatures rise.

Jamais Cascio, a founder of worldchanging.org and now writing at Open the Future published in early 2009 a very readable and insightful short book on this subject, "Hacking the Earth: Understanding the Consequences of Geoengineering." Cascio lays out the choices and ethical implications of "geoengineering" the atmosphere to control planetary heating.

In theory, several options exist: shoot sulfate particles or millions of light-reflecting disks high into the atmosphere to block the sun; fertilize the oceans with iron to encourage carbon-absorbing phytoplankton blooms; plant millions of trees to absorb carbon; spray seawater into the sky to create heat-reflecting white clouds; and somehow capture and bury carbon already in the sky.

So what to do as our rising carbon emissions heat the planet? Is there any realistic large-scale way to cool earth, or stem the heating? Volcanic eruptions have, and a recent example is the Phillippines' Mount Pinatubo. In 1991 the volcano cooled the earth when its eruptions injected massive amounts of sulfates into the atmosphere, partially blocking the sun.