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New study suggests grim changes ahead
Western drought from 2000 to 2004 killed trees and affected net carbon balance, and those conditions could become the new norm during the 21st century.
By Summit Voice
SUMMIT COUNTY — Long-term climate trends suggest that drought will become much more common across the West in the coming century, potentially redefining our definitions of wet and dry years, according to a recent paper published in Nature Geoscience.
The study started by looking at the chronic drought that hit western North America from 2000 to 2004, which was the most intense dry spell in about 800 years, according to tree-ring records. That multi-year drought helped propel the pine beetle epidemic to epic proportions and left many river basins depleted, but the researcher said those conditions could become the new norm for most of the coming century.
“Climatic extremes such as this will cause more large-scale droughts and forest mortality, and the ability of vegetation to sequester carbon is going to decline,” said Beverly Law, a co-author of the study, professor of global change biology and terrestrial systems science in the College of Forestry at Oregon State University, and former science director of AmeriFlux, an ecosystem observation network.
Global warming is causing more such climatic extremes warning that, as bad as conditions were during the 2000-04 drought, they may eventually be seen as the good old days.
Climate models and precipitation projections indicate this period will actually be closer to the “wet end” of a drier hydroclimate during the last half of the 21st century, scientists said.
Aside from its impact on forests, crops, rivers and water tables, the drought also cut carbon sequestration by an average of 51 percent in a massive region of the western United States, Canada and Mexico, although some areas were hit much harder than others. As vegetation withered, this released more carbon dioxide into the atmosphere, with the effect of amplifying global warming.
“During this drought, carbon sequestration from this region was reduced by half,” Law said. “That’s a huge drop. And if global carbon emissions don’t come down, the future will be even worse.”
It’s not clear whether or not the current drought in the Midwest, now being called one of the worst since the Dust Bowl, is related to these same forces, Law said. This study did not address that, and there are some climate mechanisms in western North America that affect that region more than other parts of the country.
But in the West, the 2000-2004, multi-year drought was unlike anything seen in many centuries, based on tree ring data. The last two periods with drought events of similar severity were in the Middle Ages, from 977-981 and 1146-1151. The 2000-04 drought affected precipitation, soil moisture, river levels, crops, forests and grasslands.
Ordinarily, Law said, the land sink in North America is able to sequester the equivalent of about 30 percent of the carbon emitted into the atmosphere by the use of fossil fuels in the same region. However, based on projected changes in precipitation and drought severity, scientists said that this carbon sink, at least in western North America, could disappear by the end of the century.
“Areas that are already dry in the West are expected to get drier,” Law said. “We expect more extremes. And it’s these extreme periods that can really cause ecosystem damage, lead to climate-induced mortality of forests, and may cause some areas to convert from forest into shrublands or grassland.”
During the 2000-04 drought, runoff in the pper Colorado River basin was cut in half. Crop productivity in much of the West fell 5 percent. The productivity of forests and grasslands declined, along with snowpacks. Evapotranspiration decreased the most in evergreen needleleaf forests, about 33 percent.
The effects are driven by human-caused increases in temperature, with associated lower soil moisture and decreased runoff in all major water basins of the western U.S., researchers said in the study.
Although regional precipitations patterns are difficult to forecast, researchers in this report said that climate models are underestimating the extent and severity of drought, compared to actual observations. They say the situation will continue to worsen, and that 80 of the 95 years from 2006 to 2100 will have precipitation levels as low as, or lower than, this “turn of the century” drought from 2000-04.
“Towards the latter half of the 21st century the precipitation regime associated with the turn of the century drought will represent an outlier of extreme wetness,” the scientists wrote in this study.
These long-term trends are consistent with a 21st century “megadrought,” they said.
This research was supported by the National Science Foundation, NASA, U.S. Department of Energy, and other agencies. The lead author was Christopher Schwalm at Northern Arizona University. Other collaborators were from the University of Colorado, University of California at Berkeley, University of British Columbia, San Diego State University, and other institutions.
Filed under: climate and weather, Drought, Environment, global warming Tagged: | carbon sequestration, climate, drought, Environment, global warming, Oregon State University, San Diego State University
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Innovative energy underwrites coverage of energy stories.
“Few seem to realise that the present IPCC models predict almost unanimously that by 2040 the average summer in Europe will be as hot as the summer of 2003 when over 30,000 died from heat. By then we may cool ourselves with air conditioning and learn to live in a climate no worse than that of Baghdad now. But without extensive irrigation the plants will die and both farming and natural ecosystems will be replaced by scrub and desert. What will there be to eat? The same dire changes will affect the rest of the world and I can envisage Americans migrating into Canada and the Chinese into Siberia but there may be little food for any of them.” –Dr James Lovelock’s lecture to the Royal Society, 29 Oct. ’07
Here is what Climate Code Red says:
–Human emissions have so far produced a global average temperature increase of 0.8 degree C.
–There is another 0.6 degree C. to come due to “thermal inertia”, or lags in the system, taking the total long-term global warming induced by human emissions so far to 1.4 degree C.
–If human total emissions continue as they are to 2030 (and don’t increase 60% as projected) this would likely add more than 0.4 degrees C. to the system in the next two decades, taking the long-term effect by 2030 to at least 1.7 degrees C. (A 0.3 degree C. increase is predicted for the period 2004-2014 alone by Smith, Cusack et al, 2007).
–Then add the 0.3 degree C. albedo flip effect from the now imminent loss of the Arctic sea ice, and the rise in the system by 2030 is at least 2 degree. C, assuming very optimistically that emissions don’t increase at all above their present annual rate! When we consider the potential permafrost releases and the effect of carbon sinks losing capacity, we are on the road to a hellish future, not for what we will do, but WHAT WE HAVE ALREADY DONE.
We, still have technology and hugh unused parts of the ocean where civilization could colonialize just off-shore in tidal communities using ocean-based farming technology during peek dry periods.
Instead of modeling dare predictions why not use some of the next white type spaces to think and plan outside the status quo.
Oceanic colonialization is cheaper than planetary colonialization, so instead of looking up, why not look down for a change!
What you people don’t seem to understand that this climate situation is self perpetuating… how can you replant when there is a major drought occurring …no water = dead old vegetation … no water = dead new vegetation. This is only the tip of the melting iceberg. There are so many more unforeseen ramifications that may all add to the final result of our stupidity.
I have worked for a number of years on solutions to the carbon and energy problems. Less than six months ago, it occurred
to me that there was a solution, one offering power on the scale of
tens of TW and cost down into the 1-2 cents per kWh.
It’s based on on old idea, power satellites, and a new “Black Swan”
development from electronics, high efficiency solid state lasers.
If we had one power satellite equipped with propulsion lasers, it
would lower the cost of raising parts to GEO for more satellites to
under $100/kg. At that price, the cost of power from space falls to
under 2 cents per kWh. That would allow making synthetic liquid
transportation fuels for $1-2 per gallon.
The problem is building the first power satellite without cheap laser
propulsion. However, it is so valuable in the role of laser
propulsion that an economic model shows it would be paid off in a few
years from the profits of selling low cost power plantseven if we have to build the first one with relatively conventional rockets.
The energy payback from power satellites is short, two months, and the profit is so high that an initial 100 GW/year business could triple in
capacity every year with only ten percent of production invested in
more laser capacity.
The model might not be correct, but if it is, then it looks like
humanity could painlessly quit using fossil fuels in no more than two
decades. If we still have warming problems, either CO2 could be
removed from the air and stored as synthetic oil back in the ground or
sunshades at L2 can be used to block as much sunlight as desired.
Amazing what grown up versions of the tiny laser diodes in CD players can do.
I have a 6000 word draft article on the topic if people want to review
and comment on it.
It would be nice if the climate studies weren’t so political. Now there is big, big money tied to this, so lots of people are in line to cash in, therein lies the skepticism. Unfortunately, only time will tell. I think here in the US, we do what we can, but down the road, the biggest polluters, India and China, don’t seem to have a plan. In the meantime, it’s understandable the skeptism, in Illinois we were told this past winter would be awful (extreme cold and snow), and it was very, very mild. The forecasters can’t seem to predict the weather tomorrow, much less a few years from now.
… and no one even mentions how cold the summer in Europe is currently, and that Australia just finished up with a very cold summer. In five years everyone will be bitching about the flooding rains.
Sorry, but you’ve got it backwards. We aren’t going to be so lucky.
Climate scientists have predicted for decades that we’d see an increased trend toward more extreme weather events, both wet and dry, and that includes torrential rain and flooding. It’s happening now, only it’s unfolding much sooner than projections. In the same way, Britain has had record rain and flooding this summer, within six months of being in record drought. More extremes, more wild swings in the weather will have a major impact on agriculture. See http://www.skepticalscience.com for more.
Remind me again why we should listen to you versus thousands of individuals who research the climate for a living………….
[...] the article: Climate: Are you ready for a western megadrought? – Summit County Citizens Voice [...]
I’m at Email: dyke.davis@yahoo.com, let’s have this conversation!