Amazon rainforest recovering from its second 100-year drought in 5 years
Life-giving rains have returned over the past two months to Earth's greatest rainforest--the mighty Amazon--after it experienced its second 100-year drought in five years this year. The record drought began in April, during the usual start to the region's dry season, when rainfall less than 75% of average fell over much of the southern Amazon (Figure 2.) The drought continued through September, and by October, when the rainy season finally arrived, the largest northern tributary of the Amazon River--the Rio Negro--had dropped to thirteen feet (four meters) below its usual dry season level. This was its lowest level since record keeping began in 1902. The low water mark is all the more remarkable since the Rio Negro caused devastating flooding in 2009, when it hit an all-time record high, 53 ft (16 m) higher than the 2010 record low. The 2010 drought is similar in intensity and scope to the region's previous 100-year drought, which hit the Amazon in 2005, according to Brazil's National Institute of Space Research. Severe fires burned throughout the Amazon in both 2005 and 2010, leading to declarations of states of emergencies.
Figure 1. Hundreds of fires (red squares) generate thick smoke over a 1000 mile-wide region of the southern Amazon rain forest in this image taken by NASA's Aqua satellite on August 16, 2010. The Bolivian government declared a state of emergency in mid-August due to the out-of-control fires burning over much of the country. Image credit: NASA.
Causes of the great 2010 Amazon drought
During the 20th Century, drought was a frequent visitor to the Amazon, with significant droughts occurring an average of once every twelve years. These droughts typically occurred during El Niño years, when the unusually warm waters present along the Pacific coast of South America altered rainfall patterns. But 2010 was a La Niña year. The 100-year drought of 2005 occurred in an El Niño-neutral year. Subsequent analysis of the 2005 drought revealed that it was unlike previous El Niño-driven droughts, and instead was caused by record warm sea surface temperatures in the Atlantic (Phillips et al., 2009.) These warm ocean waters affected the southern 2/3 of the Amazon though reduced precipitation and higher than average temperatures. Very similar record Atlantic sea surface temperatures were observed in 2010, and likely were the dominant cause for the 2010 drought.
Figure 2. The great Amazon drought of 2010 began in April, when portions of the southern Amazon recorded precipitation amounts less than 75% of normal (brown colors). The drought spread northward and peaked during July and August, but drew to a close by November when the rainy season began. Image credit: NOAA Climate Prediction Center.
The importance of the Amazon to Earth's climate
We often hear about how important Arctic sea ice is for keeping Earth's climate cool, but the Amazon may be even more important. Photosynthesis in the world's largest rainforest takes about 2 billion tons of carbon dioxide out of the air each year. However, in 2005, the drought reversed this process. The Amazon emitted 3 billion tons of CO2 to the atmosphere, causing a net 5 billion ton increase in CO2 to the atmosphere--roughly equivalent to 16 - 22% of the total CO2 emissions to the atmosphere from burning fossil fuels that year. According to Phillips et al., 2009, "The exceptional growth in atmospheric CO2 concentrations in 2005, the third greatest in the global record, may have been partially caused by the Amazon drought effects documented here." The Amazon stores CO2 in its soils and biomass equivalent to about fifteen years of human-caused emissions, so a massive die-back of the forest could greatly accelerate global warming. In late 2009, before the 2010 drought, the World Wildlife Federation released a report, Major Tipping Points in the Earth's Climate System and Consequences for the Insurance Sector, which suggested that odds of extreme 2005-like droughts in the Amazon had increased from once every 40 - 100 years, to once every 20 years. The study projected that the extreme droughts would occur once every two years by 2025 - 2050. This year's drought gives me concern that this prediction may be correct. The occurrence of two extreme droughts in the past five years, when no El Niño conditions were present and record warm Atlantic sea surface temperatures occurred, are suggestive of a link between global warming and extreme Amazon drought. If the climate continues to warm as expected, the future health of Earth's greatest rainforest may be greatly threatened, and the Amazon may begin acting to increase the rate of global warming. According to Rosie Fisher, a scientist at the National Center for Atmospheric Research in Boulder, Colorado who specializes in interactions between climate and forests, "I'm genuinely quite alarmed by this. In some ways it kind of reminds me of when they figured out than the Greenland ice sheet was melting much faster than the climate models predicted it would."
Deforestation in Brazilian Amazon falls to lowest rate on record
There is some good news from the Amazon--deforestation rates in the Brazilian Amazon have fallen 14% in the past year, and are at their lowest rate on record, according to mongabay.com, an environmental science and conservation news site that focuses on tropical forests. In 2009, Brazil passed a law committing to a 36 - 39% reduction in emissions of greenhouse gases. Reducing deforestation by 80% by 2020 was the primary method envisioned to achieve the reduction. Brazil is now four years ahead of that schedule, and no longer is the world's biggest deforester--Indonesia now cuts down more acreage of forest each year than Brazil does.
For more information
Nick Sundt at the WWF Climate Blog has a remarkably detailed post on this year's Amazon drought, and Dr. Joe Romm at climateprogress.org has another excellent post.
Phillips, et al., 2009, Drought Sensitivity of the Amazon Rainforest, Science 6 March 2009: Vol. 323 no. 5919 pp. 1344-1347 DOI: 10.1126/science.1164033.
I'll have new post Monday or Tuesday.
Jeff Masters
Reader Comments
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LOL - so this would be an indication that you believe mankind plays a part in GW? ;-)
Do you see any chances of snow with these arctic air intrusions?
Sounds good, but for two things:
1) Ten more years of inactivity waiting to "prove" warming or man's part in it is ten years too long;
2) Who would referee the decision? None of the few remaining anti-science scientists still clinging to the denier POV in 2020 would incriminate themselves, so they'd never admit they were wrong...and the argument often heard from skeptics is that if there is even a single scientist who questions AGW among the many thousands of others who believe the theory is credible, the entire theory is discardable. To such folks, the overwhelming and growing evidence staring them in the face isn't even close to enough; as such, it's highly unlikely they'll ever change their stance...so the issue can never be resolved.
Back to the drawing board, I guess... ;-)
Link
I am in Northeast Florida GTcooliebai. I am not sure where you are located, but if you are referring to the possibility of seeing snow in the Deep South with these arctic intrusions, yes, there are occasions where wintry precip can occur. Whenever we have a set up like currently where we have a extremely deep upper level trough carved out over the Eastern CONUS, there are occasions when disturbances or shortwaves move rapidly down the north or northwesterly jet flow and rotate through the base of these upper troughs. These shortwaves can bring moisture, at least through the mid levels of the atmosphere. Most often, arctic air masses like what we currently have are too dry for precipitation to reach the surface. However, there can be times where these shortwaves can be sufficient enough with deeper moisture let's say below the 700 mb level to generate precipitation at the surface. And with such a cold airmass in place with these intrusions, any moisture riding over it can generate the wintry precip.
Interesting enough, one such shortwave is being currently shown by some of the reliable model guidance runs to drop down from the intermountain west beginning Tuesday and reach the Gulf Coast late Tuesday into Wednesday. The BIG QUESTION of course is will it be enough to generate moisture in the Deep South. I say it likely will not happen, but it is something to keep an eye on anyway.
Hope I wasn't too technical in explaining this to you LOL..
Tonight
Clear
Lo 34 °F
Tuesday
Sunny
Hi 58 °F
I couldn't agree with you more Neapolitan. I was just hoping to get a show of hands now on who actually believes in their own science. Personally, I would think that the scientists that believe mankind actually plays a part in GW would be the most willing to stand by their science.
Sorry for the double post. Once again I prove my name.
Get used to it as the PDO goes cold.
Strong El Nino's like 1998 should not reappear for about another 30 years, while strong La Nina's should occur more often.
1998 was the peak and, imo, the next peak will not return for at least 20-30 years.
ENSO should be looking like pre-1976 for quite a while. IMO, this is a conundrum that requires "urgency" to save some reputations. I believe most alarmists knew (consciously or subconsciously) that they had to get action (that actually reduced CO2) to be able to claim "saving the planet" by about now. Time seems to have run out.
National Weather Service New Orleans la
1123 am CST Monday Dec 6 2010
Previous discussion... /issued 334 am CST Monday Dec 6 2010/
Short term...
some high thin cirrus moving over area having minimal affects on
temperatures this morning. Latest surface analysis indicates
freeze line from Poplarville to just north of Baton Rouge with
temperatures just getting to 32 degrees at 3 am. Lighter winds in
the lower part of the column this evening along with clear skies
should allow for maximum radiational cooling tonight. Freeze line
likely to already be down the North Shore of Lake Pontchartrain by
midnight and settle to near the Louisiana coast by 5 am Tuesday.
Will upgrade to freeze and hard freeze warnings with this package
issuance. Model guidance temperatures appear reasonable and went
pretty close with only minor changes from previous forecast
packages. Models are in very good agreement in bringing vigorous
short-wave out of northern branch across Louisiana Tuesday night.
This will likely keep min temperatures a few degrees warmer than
tonight.
A very brief and inconsequential passing of light flurries may occur across southern Mississippi counties with the passage of this fast moving feature...but not enough to warrant mention in forecast products...or to elicit any sort of actions from local officials.
Let the snow begin!
It is different IMO. Look at the ENSO graph above.
I'd agree during a warm PDO cycle (1976/77-now???), but it is turning cold, so should look like more like, as mentioned, the pre-1976 ENSO pattern vs. the post 1976 pattern.
We'll see. The next 10-20 years will be interesting as we can then see a warm vs. cold PDO cycle in the sat temp record. Will be very good data.
You better get something to keep those ears warm. That is a lot of exposure there! Looks like that nose could use a nose mitten as well.
Yeah, still debating whether to bring the orchids in. Way too many!
Bring them in if you can, or at least cover them. I made a big mistake last year. (P.S. You know how many time I heard "I told you so")
He doesn't like wearing hats when his picture is being taken. But thanks for the advice.
Sometimes I hate the EURO.. Maybe the models will cha cha back to bringing a coastal snowstorm for Long Island ;)
Accuweather is putting more confidence in NO snow for the big cities this weekend, compared to yesterdays model runs. I'm hoping they will shift the snow back towards the east.
I guess that is true. Not to mention the manners of not wearing a hat while indoors. Still, why the long face? ;-)
If you were forced to eat gernuckenflucken and vennskapkake, you would have a long face too.
BTW...New Blog
Yep, supposed to drop into the 20s here in South Florida tonight. One more thing Jeff, didn't you say FSU was gonna win? LOL
Forget the hat, hook the dog up with some fur!
LOL that's alright I like technical information Thank You.
At any rate, it's pretty chilly for Nassau on 7 December...
How long were accurate records kept?
It is VERY unscientific to use such ambiguous terms when talking about what most folks regard as science.
It is no wonder at all why there is ongoing controversy and doubt about so-called scientific subjects such as "global warming", "biological evolution of life from non-living matter", "worm holes", "multiple universes", etc.
These and other issues that cannot be experimented upon directly and repeatedly are beyond the realm of science. Therefore, all statements regarding such issues are guesses at best and total nonsense at worst.
I am only complaining about writers stating as fact that which is conjecture at best.
Please grow up and learn some critical thinking skills!
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