A field of cereals burning near the town of Voronezh, Russia, after weeks of searingheat and virtually no rain in the summer of 2010.Credit Associated Press
As has often been noted here on the Green blog, one of the biggest uncertainties humanity faces regarding climate change is the potential effect on the world’s food supply.
If there is a risk that global warming and related changes could hit much sooner and much harder than scientists are expecting, agriculture could be the crucial realm where that occurs. In fact, we have already
entered an era of sharply higher global food prices, with climate change as one of the likely causal factors.
A new paper from
researchers associated with Tufts University puts the overall risk in perspective. It is billed as a working paper, meaning it has not gone through formal scientific review, but it strikes me as worth highlighting
nevertheless. The findings pretty closely match the conclusions presented in some of my reporting from 2011.
The authors, Frank Ackerman and Elizabeth A. Stanton, point out that in the 1990s, research suggested that climate change would be fairly benign for agriculture. The first few degrees of warming would help agriculture
expand in chilly regions, the thinking went, and the rising level of atmospheric carbon dioxide would act as plant fertilizer, increasing crop yields. More recent science has cast sharp doubt on some of
those conclusions. Read more…
When I first met the NASA climate researcher Gavin Schmidt a few years ago, we discussed the proliferation of material on the Internet attacking mainstream
climate science. I asked him whether he thought climate contrarians were flirting with conspiracy theory in their views.
Photo
Credit WND Books
“Flirting?” he said. “No. They’ve already had conspiracy theory out on a hot date, and now it’s the morning after and they’re sitting up in bed, having coffee.”
I happened to recall that conversation the other day as I read the latest chapter of a remarkable back-and-forth between mainstream researchers and climate contrarians.
It all started last year, when a social scientist named Stephan Lewandowsky, of the University of Western Australia,
and two colleagues published a rather provocative paper. It was based on an
anonymous Internet survey of the readers of climate blogs. Read more…
Alessio Rovere, a Columbia University researcher, examined an ancient shoreline deposit in Cape Agulhas, South Africa. Dunes moving inland ahead of a rising sea are believed to have buried trees at the site, with the decaying trunks producing the unusual features at center.Credit Justin Gillis/The New York Times
In my article in Tuesday’s Science Times about the risks of long-term sea level
rise, and in an accompanying podcast, I reported on the link between past instances
of global warming, caused by natural fluctuations in the climate, and higher shorelines.
Based on a study of these past variations, some scientists believe that even if we stopped burning fossil fuels tomorrow, we would be due for a substantial rise in sea levels over the long term as ice sheets
slowly respond to the warmer temperatures brought on by the greenhouse gases that humans have already dumped into the atmosphere.
The paleoclimate record, as it is known, suggests that even a slight amount of global warming can produce a rise of 25 to 30 feet. And if scientists are anywhere close to right in their projections, the warming
over the coming century due to human activity is going to be more than slight. That means a long-term rise in sea level of as much as 80 feet cannot be ruled out. Read more…
Left, the projected change in annual average temperatures in 2071 to 2099 (compared with 1971 to 2000) if rapid reductions in emissions are achieved; right, the projected change if increases in emissions continue.Credit National Climate Data Center; Cooperative Institute for Climate and Satellites-N.C.; data from Coupled
Model Intercomparison Project
The natural conservatism of science has often led climatologists to be cautious in their pronouncements about global warming. More than once they have drawn criticism for burying their fundamental message – that society is running some huge risks — in caveats and cavils.
To judge from the draft of a new report issued by a federal advisory committee, that hesitation may soon fall
by the wayside. The draft, just introduced for public comment before it becomes final, is the latest iteration of a major series of reports requested by Congress on the effects of climate change in the United
States.
I caution that it is a draft, so we don’t know what final language will make it into the report. I am always hesitant to give too much credence to drafts that could change substantially, but in its current
form, the document minces no words.
“Climate change is already affecting the American people,” declares the opening paragraph of the report, issued under the auspices of the Global Change Research Program,
which coordinates federally sponsored climate research. “Certain types of weather events have become more frequent and/or intense, including heat waves, heavy downpours, and, in some regions, floods
and droughts.
“Sea level is rising, oceans are becoming more acidic, and glaciers and Arctic sea ice are melting. These changes are part of the pattern of global climate change, which is primarily driven by human activity.” Read more…
Workers unloaded sugar cane at a wholesale market in the southern Indian city of Chennai. Food prices declined modestly last year, with the dips concentrated among some of the higher-value commodities like sugar, oils and dairy products.Credit Reuters
World food prices ended the year with a slight decline, and for 2012 as a whole they were 7 percent below prices of 2011, the Food and Agriculture Organization of the United Nations reported on Thursday.
Food prices have been one of the most troubling aspects of the international economic situation for several years now, so this is a spot of good news. But prices, driven by rising demand in developing countries
and supply constraints that include climate change, remain well above levels of the 1990s. The price
run-ups in recent years, particularly in 2008 and 2011, have led to the biggest increases in world hunger in decades.
The 2012 declines reported by the F.A.O. were concentrated among some of the higher-value commodities like sugar, oils and dairy products. The most important and politically sensitive prices, for the grains
that supply most human calories, were down only 2.4 percent in 2012 from the previous year. Read more…
I would guess a few Green readers had the experience, over the holidays, of arguing yet again about global warming with a parent or brother-in-law who thinks it’s all a big hoax. Maybe there’s some undiscovered
substance in roast turkey that makes people want to pick fights around the dinner table.
I’m happy to report that the new edition of this slender volume is an improvement — perhaps even the single best thing written about climate change for a general audience. It is a little longer
than the first edition, 93 pages instead of 85, but it’s still an easy read — most people will get through it in a single sitting.
The new version updates the science to the latest numbers, of course, but it also adds a couple of chapters about the potential solutions to climate change and the bizarre politics that have cropped up around
it in recent years. Read more…
For those who might be keeping score, we just passed the 333rd consecutive month of global temperatures above the 20th-century average.
November 2012 was the fifth-warmest November since records began in 1880, the National Oceanic and Atmospheric Administration said in its monthly climate report.
The agency calculated that the 10 warmest Novembers on record have all occurred within the past 12 years.
The last time global temperatures came in below the 20th-century average for the month of November was in 1976, and the last time any month came in below the average was February 1985. Read more…
Some Green readers have probably heard by now that a draft of the next big United Nations report on climate change has leaked.
Science@NASA
The agent of the leak is a rather colorful climate contrarian named Alec Rawls, who essentially claimed,
on the basis of a single sentence in the draft, that the entire edifice of climate science is about to collapse. In his interpretation, the group putting the report together, the Intergovernmental Panel on Climate Change,
is about to acknowledge the validity of a longstanding fringe theory: that cosmic rays have a huge influence on the earth’s climate.
This claim turns out to be an overstatement, to say the least. But first, what do the leak and the accompanying flurry of reaction on blogs tell us about the United Nations exercise of periodically summarizing
climate science?
These reports come out roughly every five years. They are unlike anything else in science that I know
of: an attempt to digest the many thousands of relevant papers and discern a global scientific consensus about the state of climate science, the likely impacts of climate change, and the policies that might
be effective in countering the risks.
The exercise is a special type of response to a unique global problem. Ultimately, the reports are supposed to help governments decide what steps to take to act on their own stated commitment under a global
treaty to “prevent dangerous anthropogenic,” or human, “interference with the climate system.” Read more…
Ted Scambos/National Snow and Ice Data CenterAn Antarctic ice stream carries ice toward the ocean.
The future of Antarctica on a warming planet has long been one of the great uncertainties in climate science.
The western part of that continent has a low-lying ice sheet that appears to be highly vulnerable to attack by warmer ocean water. Some signs suggest that the ice sheet is in the early stages of a collapse that could eventually have a profound effect on sea level.
The much larger, higher, colder ice sheet in eastern Antarctica is another story. Scientists have long thought that not only might it be stable in a warmer world, but it might even gain ice, as some computerized
forecasts suggested. The idea was that a warmer atmosphere holding more moisture would lead to greater snowfall, but eastern Antarctica would still be cold enough to preserve that snow as glacial ice.
Some research even suggested that the gain might be enough to offset much of the water pouring into the ocean from melting ice elsewhere, helping to limit the rise in sea level.
Now a new study throws cold water, so to speak, on this notion. Read more…
Environmental Working GroupAn analysis shows that from 2008 to 2011, water quality was rated “poor” or “very poor” at 60 percent of the 98 stream segments monitored by the Iowa Water Quality Index.
As many people know, the astounding increase in agricultural output that marked the latter half of the
20th century came at a high environmental price. Agriculture is a major contributor to global warming, and runoff from farm fields helps pollute rivers and streams.
In the United States, nothing quite symbolizes this issue like the dead zone in the Gulf of Mexico, near the mouth of the Mississippi
River, which is largely a consequence of fertilizer runoff from the Midwestern farming region.
Now the Environmental Working Group, a Washington outfit known for its work on agricultural issues, is calling attention to the lingering problems with a new report titled “Muddy Waters.”
While it focuses on water quality in Iowa, the report makes a broader point about the relationship between agriculture and the environment. When the Clean Water Act was adopted in 1972, farms were largely exempted
from its requirements. That means getting farmers to adopt practices that limit runoff has been a voluntary activity. Read more…
When frozen hard, permafrost supports the ground surface the way a concrete pillar supports a building. When permafrost thaws, the ground can turn mushy and collapse, leading to the formation of a bog or lake that is likely to give off methane. This collapsing ground, known as a thermokarst, can cause trees to lean at crazy angles, as they do at this site near Fairbanks. The results are called “drunken forests.”Credit Josh Haner/The New York Times
The greatest single uncertainty about climate change is how much the warming of the planet will feed on itself.
As the temperature increases because of human emissions, feedbacks could cause new pools of carbon to be released into the atmosphere, magnifying the trend. Other types of feedbacks could potentially slow the
warming. Over all, climate scientists have only best guesses about how these conflicting tendencies will balance out, though most of them think the net result is likely to be a substantial rise in the planet’s
average temperature.
As I reported last year, one of the most worrisome potential feedbacks
involves the permafrost that underlies a quarter of the Northern Hemisphere. Buried in that frozen ground is a lot of ancient organic material, containing twice as much carbon as now exists in the atmosphere.
The permafrost is starting to warm and the carbon to escape.
A new report, released Tuesday morning by the United Nations Environment Program, warns that scientists do not have a sufficient handle on the situation. It calls for new monitoring efforts and for a formal
assessment of the permafrost feedback by the Intergovernmental Panel on Climate Change, the U.N. body that periodically reviews and summarizes climate science.
The report will be considered in the next few days at a climate negotiating session in Doha, Qatar. If current estimates about the potential for carbon release from permafrost are correct, they mean that tackling climate change is going to be even harder than it once seemed. That is because the long-running global negotiations
over emission limits do not take much account of the potentially large carbon release from permafrost.
In essence, the permafrost feedback is a big new emissions source that makes the math of controlling climate change harder than ever.
Josh Haner/The New York TimesA warming climate creates summertime water stress for trees like these mountain pines in Montana, making them more vulnerable to attack by beetles. The gray trees above died several years ago.
One of the great scientific tasks of the day is to understand how and why trees die. It may seem like a question that would have been answered many decades ago, but it was not — at least not at a detailed physiological level. Now, amid growing signs worldwide that forests are at risk as the climate changes, scientists are trying to catch up to events.
Lately, more and more evidence is pointing toward a mechanism known as hydraulic failure as the culprit in many large-scale forest die-backs. This occurs when drought reduces the flow of water into tree roots.
The trees take measures to limit the loss of water through their leaves, but trees need water flowing through them as much as humans need blood. Eventually, if the drought is bad enough, the tiny tubes that
carry water up the trunk of the plant can fill with air bubbles.
Detailed understanding of this mechanism may still be developing, but anybody who has forgotten to water a house plant has seen the consequences. The flow of water through the body of the plant is interrupted,
and unless moisture is restored to the soil, it can droop and eventually die.
Now comes a surprising new paper from an international research team presenting ominous findings about the risks to forests from global warming and its accompanying water stress. Read more…
Associated PressA road lay in ruins on the western end of Dauphin Island, Ala., after Hurricane Katrina passed through in 2005.
In an article in The Times, my colleague Felicity Barringer and I explore the
issue of whether it makes sense to keep rebuilding, largely at the expense of federal taxpayers, in hazard-prone coastal areas. We made passing reference to a debate over the causes of beach erosion in Dauphin
Island, Ala.
The situation there is worth exploring a bit further, for it sheds light on some of the broad issues the nation will have to confront along its coastlines in coming decades.
As we mentioned, local residents blame the Army Corps of Engineers for their erosion problems. In a role similar to the one it plays in many coastal regions, the Corps conducts frequent dredging operations in
the nearby Mobile Ship Channel, to the east of Dauphin Island, so that oceangoing cargo vessels can make use of the Port of Mobile.
Why would that make any difference?
Many people imagine that beaches and barrier islands are just mountains of sand that sit unmoving at the edge of our shores. In reality, they are highly dynamic systems, constantly moving and adjusting to storms,
currents and changes in sea level.
Sand actually flows up and down our shorelines, by the billions of tons, and often there’s a net direction to this flow,
known as “littoral drift” or “longshore transport.” That is to say, averaged over time, more sand flows one way than the other. The beaches we see above water are but a small
part of this system. Far more sand lies offshore, and these unseen hills of sediment play a crucial role in the overall sand supply to beaches down the line. Read more…
Associated PressWomen en route to a water collection point near Ngara, Tanzania.
More than anything else, climate change is a water problem. Scientists expect more coastal flooding and possibly more inland flooding. They expect higher temperatures and greater evaporation to deplete water
resources, creating risks for the food supply. They believe sea-level rise will eventually render some regions uninhabitable.
But a new paper published on Sunday in the journal Nature Climate Change suggests that the outlook on fresh water may
not be entirely bad.
In many places around the world, groundwater is the most important source of local water supplies. And the new analysis, by Richard G. Taylor of University
College London and a half-dozen other scientists, found that the more intense rainfall expected in many parts of the world as a result of climate change may help to recharge the aquifers that supply groundwater.
Their analysis is based on a 55-year record compiled in Tanzania that allowed them to study the relationship between groundwater recharge and rainfall. Their basic finding was that a disproportionate share of
the recharge came from heavy storms. Read more…
NASASandy, a massive hybrid of a once-tropical storm and a mid-latitude storm, moved inland Tuesday.
Was the bizarre storm called Sandy a product, in whole or in part, of human-induced climate change?
That may not be a top-of-mind issue for the millions of people who will spend coming weeks recovering from the damage. But it is an important scientific question, one whose answers could shed light not just
on why this storm happened but also on what to expect in the future.
The first thing to say is that climate scientists are just not in a good position to answer it yet.
Some of them are already offering preliminary speculations, true, but a detailed understanding of the anatomy and causes of the storm will take months, at least. In past major climate events, like the Russian
heat wave and Pakistani floods of 2010, thorough analysis has taken years — and still failed to produce unanimity about the causes.
But in interviews on Tuesday, several climate scientists made some initial points. A likely contributor to the intensity of Sandy, they said, was that surface temperatures in the western Atlantic Ocean were
remarkably high just ahead of the storm — in places, about five degrees Fahrenheit higher than normal for this time of year. In fact, part of the ocean was warmer than it would normally be in September,
when accumulated summer heat tends to peak. Read more…
