backtop


Print 55 comment(s) - last by Polynikes.. on Sep 15 at 3:09 PM


  (Source: StormVideographer.com)
It might be a little premature to declare a primary tenet of global warming theory "invalidated" ...

Analysis of rainfall and surface moisture trends have led to a number of studies investigating whether the Earth has been undergoing drying, or whether drying is reversing.

Fellow DailyTech blogger Michael Asher recently reported on one study that analyzed historical rainfall data between 1900 to 2000, and using wavelet analysis concluded that droughts were decreasing, and that major drought events were decreasing as well.

Another study, released just days before by NASA's Goddard Institute for Space Studies (GISS), analyzed the data on rainfall and concluded that worldwide the Earth is undergoing significant drying effects.  In particular, much of the Mediterranean area, North Africa and the Middle East are rapidly becoming drier. 

The study goes on to use this data to predict current weather patterns.

This study continues a long chain of research which supports a unanimous conclusion that the Earth is experiencing significant drying.

In 2006, the British government funded a climate study carried out by the Met Office Hadley Centre for Climate Prediction and Research. 

Its conclusion: global drought increased 25 percent in the 1990s.

It also modeled possible future weather scenarios and found that indicated that extreme drought could affect 30 percent of the world's land surface, up from the current span of 3 percent.  Severe drought (the next worse) would rise from 8% land area to 40%, and mild drought would rise from 25% to 50%.

In 2005, the National Center for Atmospheric Research (NCAR), a U.S. government funded research center, released a study that the percentage of Earth's land area stricken by serious drought more than doubled from the 1970s to the early 2000s.

It also found that drought had increased and surface moisture had decreased, on average, worldwide.

Along the lines of the study mentioned in the other Dailytech article, it found that water vapor in the air and global precipitation have increased over the past few decades--however, warming caused the moisture to evaporate at a faster rate, and land moisture levels have been dropping, leading to droughts.

To examine how soil moisture has evolved over the last few decades, the NCAR researchers produced a unique global-scale analysis using the Palmer index, which for decades has been the most widely used yardstick of U.S. drought. The Palmer index is a measure of near-surface moisture conditions and is correlated with soil moisture content.

Interestingly, the study indicated that the U.S. has become wetter over the past 50 years, while most of the rest of the Northern Hemisphere has dried.

While rainfall has increased worldwide, the study found that it has decreased in Africa's Sahel and East Asia, leading to further expansion of dry soils.

The conclusions of these studies: the U.S. may be getting wetter, and rainfall may not be decreasing, but land moisture is definitely decreasing, due to increasing temperatures.  Decreased land moisture will lead to more droughts, and more extreme droughts, as the soil experiences further decrease in moisture.

While this is only one element of global warming and climate change theory, it certainly seems premature to declare it "invalidated," as some critics are inclined to proclaim.


Comments     Threshold


This article is over a month old, voting and posting comments is disabled

RE: Not correct
By JasonMick (blog) on 9/12/2007 3:50:25 PM , Rating: 2
Aside from these papers, there are numerous articles which discuss record droughts both in the U.S. and abroad, which support the conclusion that while precipitation may be increasing worldwide, the desparity between wet and dry areas is increasing.

For example, from the Environmental News Network (which I know you probably don't approve of)

"Drought Reduces Level of Lake Okeechobee, Threatens Water Supply in South Florida"
http://www.enn.com/energy/article/6654

"China Creates Artificial Snowfall in Tibet"
http://www.enn.com/sci-tech/article/6392

"North Carolina Drought Worsens, Lowest Streamflows In More Than 110 Years"
http://www.enn.com/climate/article/22700

"USDA Declares Colorado, Iowa and Maryland Disaster Areas In 3 States"
http://www.enn.com/climate/article/22293

"Australian Water Crisis Could Be Worse Than Thought"
http://www.enn.com/energy/article/6573

"Indiana: High Temperatures, Low Precipitation Creating Many Problems"
http://www.enn.com/climate/article/22156

And from other sources....

Florida's drought
http://stormvideographer.com/blog/2007/04/04/flori...

Current U.S. drought
http://drought.unl.edu/dm/monitor.html

California's driest year in 230 years
http://meteora.ucsd.edu/cap/western_drought.html

Australian drought
http://home.iprimus.com.au/foo7/drought.html

U.S. droughts
http://www.dailyyonder.com/drought-2007-what-maps-...

America's Worst Drought Since the Dustbowl
http://news.independent.co.uk/world/americas/artic...

N.Y. Times on Drought Conditions Worldwide
http://query.nytimes.com/gst/fullpage.html?sec=hea...

There is a lot of data out there that shows that 2007 has been a very bad drought year, and much data to show that droughts resulting from soil drying due to warming are an increasing trend. It is hard to deny this fact, even if one or two studies do some sort of statistical analysis to skew the numbers to make it look like this phenomena is not occuring.


RE: Not correct
By TomZ on 9/12/2007 4:04:26 PM , Rating: 2
Most of these articles talk about current or recent drought conditions - I don't see anything which really looks at the longer-term trend, not to mention tie-in to global warming, not to mention tie-in to human CO2 generation.

It seems like you're engaging in some kind of shotgun debating technique, to me at least.


RE: Not correct
By masher2 (blog) on 9/12/2007 4:57:47 PM , Rating: 2
> " there are numerous articles which discuss record droughts both in the U.S. and abroad"

Article 2: Nothing to do with "record drought". It demonstrates Chinese efforts to combat drought in case of future need .

Article 4:
quote:
USDA said Delta County, Colorado, was designated a natural primary disaster area because of losses caused by a freeze that occurred in April. Rio Blanco County, Colorado, also was impacted by frost and freezing temperatures in June and drought that is ongoing since May.

USDA said Audubon, Crawford, Fremont, Harrison, Monona, Pottawattamie, Polk and Tama counties in Iowa had a freeze in early April...
Were you including this as a joke?

Article 5: New South Wales is experiencing drought conditions, but I don't see anything about a "record drought".

Article 6: No "record droughts" here either. Some portions of Indiana are drier than they've been in 50 years. Meaning, they were drier in 1960 than today.

Article 7: Same area as article 1. It's still just one small area, no matter how many times you report it.

Article 8: Just a map of current US conditions. No "record breaking" droughts mentioned.

Article 9: "California has a history of drought, sometimes lasting 100 years, as far back as 1,100 years ago". Sounds like nothing new for the area to me.

Article 11: No "record droughts" mentioned. Some areas in the US are experiencing a drought (which you've already covered in prior links).

Article 12: Entitled, "America's Worst Drought Since the Dust Bowl". Meaning, "drought was worse in the 1930s than today". Explain again how you believe this proves global warming is responsible? And how many times are you going to repeat the same areas?

Pick a year, any year at all, and you'll find some regional areas will break records. Hottest temperature, coldest temperature, most rainfall, least rainfall, most storms, fewest storms, etc, etc. This is natural, normal, and in no way indicative of anything at all, other than natural variability.


RE: Not correct
By JasonMick (blog) on 9/12/2007 5:32:29 PM , Rating: 2
The point is the worldwide prevalence of these droughts.

quote:
Were you including this as a joke?


Article 4:

"Separately, 22 Maryland counties were declared disaster areas because of drought and excessive heat that has occurred since June."

Middle of the article, mentions droughts, clearly.

I agree that some of these are not "record-breakers", but it does show an overall increase in incidence of droughts.

quote:
Pick a year, any year at all, and you'll find some regional areas will break records. Hottest temperature, coldest temperature, most rainfall, least rainfall, most storms, fewest storms, etc, etc. This is natural, normal, and in no way indicative of anything at all, other than natural variability.


Soil moisture is a far better way to look at whether droughts are occuring/will occur, as preciptation can increase, but given sufficient increase in evaporation, the soil can actually dry.

For some more good reading:

"Drought halts Wildebeest Trek"
http://observer.guardian.co.uk/world/story/0,,1989...

"Drought devastates Romanian agriculture: World Vision plans relief"
http://www.reliefweb.int/rw/RWB.NSF/db900SID/SJHG-...
http://observer.guardian.co.uk/world/story/0,,1989...

"Major Drought in Moldova"
http://www.bbc.co.uk/weather/world/news/25072007ne...

"Record Drought in Turkey"
http://mnweekly.ru/world/20070816/55268085.html


RE: Not correct
By masher2 (blog) on 9/12/2007 5:44:05 PM , Rating: 1
> "Middle of the article, mentions droughts, clearly."

Right...after mentioning all the areas hit by record cold, it mentions some that have droughts. What was your point again?

> "it does show an overall increase in incidence of droughts"

How so? Scrounging up a few random web links is not a statistical survey, and proves nothing. I can quickly round up several dozen links showing areas which have had record-breaking cold recently. Does that prove the globe is getting colder?


RE: Not correct
By theflux on 9/12/2007 7:22:28 PM , Rating: 2
quote:
I agree that some of these are not "record-breakers", but it does show an overall increase in incidence of droughts.


No, actually it doesn't.


RE: Not correct
By sxr7171 on 9/13/2007 12:28:37 PM , Rating: 2
Coming up with some examples of droughts is poor form. It means nothing. Come back with some real ammunition next time.


RE: Not correct
By sxr7171 on 9/13/2007 11:54:06 AM , Rating: 2
You speak of many US droughts while citing an article that says the US is getting moister. Some record droughts here and there do not an alarming catastrophic drought-prone world make.


"I modded down, down, down, and the flames went higher." -- Sven Olsen

Related Articles
Researchers: Droughts Becoming Less Common
September 12, 2007, 9:13 AM
















botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki