Cites Natural Causes
Tom Spears, Canwest News Service
It’s wrong to blame our warming climate on human pollution alone, says a major analysis by U. S. climate scientists who say North America’s warming and drying trend also has important natural causes.
Natural shifts in ocean currents have caused much of the warming in recent decades, and almost all of the droughts, says the U. S. National Oceanic and Atmospheric Administration (NOAA).
Most climate researchers today deal exclusively with man-made “greenhouse” gases, and often dismiss suggestions of naturally caused warming as unscientific.
Yet NOAA says Western Canada has warmed by two degrees and Eastern Canada hasn’t warmed at all because flows of air from naturally shifting Pacific currents have affected the West most.
The lengthy re-analysis of climate data doesn’t dispute that greenhouse gases from fossil fuels cause a warmer climate. But it raises questions about the details: How much warming? How many causes? And why isn’t it the same every-where?
It also stresses that we don’t understand climate as well as we like to think, because scientists only have good data from about 1948 onward.
“Most of the warming [worldwide] is the consequence of human influences,” said Martin Hoerling, a NOAA climate scientist. But he said the question remains, “What does that mean for my backyard?”
Policy-makers need to know whether natural changes or pollution is causing local conditions such as the current drought from California across to Texas, the report notes.
“All regions are not participating [in warming] at the same rate as the global temperature is changing,” Mr. Hoerling said. Some in the West are warming rapidly, and some not at all (the southeastern United States and Atlantic Canada).
Oceans carry vast amounts of heat, releasing heat and moisture into air, which then travels inland. The re-analysis focused on this fact.
Some of the changes in North America’s warming trend of the past half-century have been due to shifting ocean currents, the NOAA team found. It estimates the “natural” change is substantial and could be close to half of all warming in North America (though it is still less than the amount caused by greenhouse gases.)
The study found:
– The 56-year trend of annual surface temperature showed a rise of 0.9C, plus or minus one-tenth of a degree.
– The greatest warming — up two degrees — has taken place across Alberta, Saskatchewan, Yukon and Alaska. Quebec and Atlantic Canada stayed cool.
That East-West difference “is not what we would expect from the effect of greenhouse gases alone,” Mr. Hoerling said. Greenhouses gases should have influenced both. However, NOAA believes Western Canada is receiving more warm air due to shifting patterns of the Pacific Ocean currents.
– Variations within North America “are very likely influenced by variations in global sea surface temperatures through the effects of the latter on atmospheric circulation, especially during winter.” The term “very likely” is defined as a chance of 90% or more.
– It’s “unlikely” that patterns of drought have changed due to global warming caused by human pollution. Rather, natural shifts in ocean currents are probably to blame. For instance, the current drought in Texas and the southwest are due to La Nina, a Pacific Ocean current that starts and stops periodically (such as El Nino), and cuts off the movement of moist air inland. Warmer temperatures from greenhouse gases, however, would worsen the basic drought.
– Seven of the warmest 10 years since 1951 occurred in the decade from 1997 to 2006. The data in the study cover only to the end of 2007.
The study, Reanalysis of Historical Climate Data for Key Atmospheric Features, was completed in December but hasn’t been widely publicized.
(Read the report here, PDF 8 MB)
Meanwhile, a study published in the research journal Science last week raises further questions about our under-standing of global warming. It disputes the theory that global warming is causing more major hurricanes.
NOAA and the University of Wisconsin at Madison blame, instead, a reduction in the number of volcanic eruptions and dust storms near the equator. When there’s less airborne dust and ash, more sunshine reaches the planet’s surface, which warms the tropical oceans and spawns strong hurricanes.
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ROLLERBALL is coming soon to an arena near you
What warming?
http://motls.blogspot.com/2009/04/rss-msu-006-c-month-on-month-cooling.html
Steven Hill
It seems that roller balls appear only in summertime….until real americans roll on him
Pete Simmons (05:15:54) :
Gee, Pete, that was very well done. I checked out YOUR “Fool On The Hill” (very appropriately named, I must say; self knowledge is a wonderful thing) site and noticed that there does not seem to be a way to post comments. Very open minded of you. That anti-Christian diatribe at the bottom was a very nice touch.
I’m going to throw this out there. realclimate.org has a post up about science vs advocacy, and I pointed out that their criticism applies to themselves as well, using the example of the CO2 time lag. I am curious what your response is to Chris Colose’s response:
It should not at all be surprising that CO2 can “lag” planetary temperature changes. After all, changes in vegetation and other biological activity from enhanced (reduced) ice cover or temperatures, changes in the solubility of gases in ocean water, etc should alter atmospheric chemistry. Such carbon cycle feedbacks, in fact, were predicted before it was observed in the ice core record.
In order to put as much CO2 into the atmosphere at the end of each ice age as is recorded in proxy records, the deep ocean must have been involved. A principle mechanism is the creation of upwelling favorable conditions in the Southern Ocean to vent CO2 from the deep waters, particularly as the Intertropical Convergence Zone shifted closer to the equator and the southern westerlies shifted further toward Antarctica. This is discussed on my blog with corresponding comments from the lead author of a recent Science paper on the issue. Key mechanisms and ideas resulting in changes in biogeochemical boundary conditions going along with temperature changes between glacial-interglacial cycles is described in
http://faculty.washington.edu/battisti/589paleo2005/Papers/SigmanBoyle2000.pdf
One of the key papers cited by global warming skeptics for making the “CO2 lags temperature” (for instance it is done so in the popularized “Swindle Video”) argument is Caillon et al 2003. In their conclusion, they specifically note that changes in pCO2 have come essentially exclusively from anthropogenic sources in the industrial era. As gavin noted the rate of glacial-interglacial CO2 variation is significantly less (he quotes ~20 ppm/degree C change) and at least an order of magnitude slower than today. Isotopic signatures and increased carbon in the oceans show that the CO2 rise today is not from natural feedback.
It would be much more common to see CO2 “lagging” in this context because you don’t expect massive injections of “externally forced” carbon into the atmosphere, although relevant paleo-examples can be found if you look hard enough (e.g., the PETM). Because rather abrupt injections at the rate which occurred during the PETM or industrial age is rare in the geologic record, there are no very good analogs for climate change on the timescale of a century associated with greenhouse gases. The paleoclimate record is very consistent however concerning the relationship between CO2 and global temperatures over geologic timescales.
In contrast to chemical feedbacks associated with disturbances in the ocean and biosphere, CO2 warms the planet through established principles of radiative physics, particularly the ability to allow the inflow of energy in the planet system to exceed outflow. Accordingly, thinking of CO2 as “leading” or “lagging” all the time is not very good, since the two mechanisms are intrinsically related…although important carbon feedbacks from natural temperature changes occur on timescales longer than the last few decades, and so the change in CO2 is essentially all from fossil fuel emissions and deforestation/land use changes.
AGW makes no claims about the ability of “other factors” to be involved in climate change– either contemporary or in the past. Changes in the Earth’s orbit and many other things can change temperature. The relevant claim and the dictates of the physics says that CO2 must warm the planet, regardless of any superimposed natural variability. There is no contradiction between orbital changes putting more sunlight at the poles on millennial timescales to take the planet in and out of ice ages, and the ability of modern CO2 to cause warming. The paleo-record confirms that we understand the basic workings of climate change much more than it contradicts it.
“AGW makes no claims about the ability of “other factors” to be involved in climate change– either contemporary or in the past. Changes in the Earth’s orbit and many other things can change temperature. The relevant claim and the dictates of the physics says that CO2 must warm the planet, regardless of any superimposed natural variability.”
What claims does AGW make? And how do those stand up to observation?
Mike N.,
Sorry, pal, but your thesis goes up in smoke when you state:
Yeah, the ‘relationship’ is that rises in CO2 follow temperature rises.
Any warming caused by CO2 has long since been incorporated into the planet’s current temperature. Log scale effect, dontcha know.
I have yet to see any credible evidence showing that further rises in CO2 will result in a warming climate: click
The planet itself is falsifying your conjecture. And to pretend that RealClimate isn’t advocacy doubled and squared is nothing but psychological projection.
Smokey gets a special award for reading contribution today. Bravo!
Smokey wrote in response to Mike N “The planet itself is falsifying your conjecture.”
Agreed.
The fact that there could be this much cooling…even in the face of increased CO2….yet the planet still cools. Fancy that.
Speaking of “warming” and the global temp spike in 1998….ya’ll might want to mosey on over to http://wattsupwiththat.com/2009/04/01/nasa-headline-deep-solar-minimum/ and check out Hotrod’s post at (17:54:00) :
Comparing the 1998 spike in global temperatures, to a steep-walled, non-linear rogue wave.
Damn fascinating connection.
Chris
Norfolk, VA, USA
The above report would be like saying that the snowfall record set in Spokane, Washington, of recent vintage, as in the past 24 hours, was 49% caused by natural variation, and 51% caused by global warming. In 1920 record snows were recorded in a system that has data since 1881. It would be reasonable to say that there wasn’t global warming back then. Spokane was not exactly a coal belching metropolis. So what is causing this extreme weather now? Same area. Same extreme weather pattern variation. But different cause? That seems so disingenuous. Any investigator must deal with the first encountered pathology. What was it back then? An arctic jet stream loop? More than likely, yes. Also probably a very cold Northern Pacific ocean. What is going on now? An arctic jet stream loop and a very cold Northern Pacific ocean. It really is 1 plus 1 equals 2. Unless you are an AGWer who says with a straight face that global warming can mimic the affect of a cold ocean and jet stream loop on poor “had enough of snow” Spokane.
RECORD REPORT
NATIONAL WEATHER SERVICE SPOKANE WA
126 AM PDT FRI APR 03 2009
THE SNOWFALL AT SPOKANE AIRPORT IN THE PAST 24 HOURS WAS 2.4 INCHES.
THIS WAS A RECORD FOR THE MOST SNOWFALL FOR THIS DATE. THE PREVIOUS
RECORD OF 1.2 INCHES WAS SET IN 1920. RECORDS HAVE BEEN KEPT AT
SPOKANE SINCE 1881.
Nasif Nahle (07:37:04) :
Out of topic but interesting: Medieval Warming Period was warmer than the last recent warming and it was global. Now the debate centers on what caused the MWP. From Science Magazine this week:
http://www.sciencemag.org/cgi/content/full/324/5923/78
That paper says the MWP (in EUROPE) was caused by a long positive NAO. A positive NAO warms Europe- but doesn’t it also cool Northern Canada and Greenland?
It seems to me that if the NAO is responsible for the MWP, then the MWP couldn’t have been global- the European warming being offset by Canada and Greenland cooling.
Dave Middleton (and others) :
The NOAA study only deals with the causes of climate changes in North America, NOT the entire globe.
Chris V.:
“- the European warming being offset by Canada and Greenland cooling.”
The Viking settlements in Greenland during MWP are documented historic facts. The vikings even had agriculture there. They were extinguished in the 15th century, presumably by much colder climate. Last year of recorded settlement is 1408. You are aware of these historic facts, aren’t you Chris?
Chris V.:
From Lubos Motl:
In other words, global sea ice is increasing! And since the AGW/CO2 hypothesis claims that the planet is warming globally, something isn’t right.
What isn’t right? Obviously, it is the incorrect assumption that global warming is occurring. If global sea ice is seeing a net increase overall, then the AGW/CO2 hypothesis takes another fatal hit.
How many hits does your AGW/CO2 hypothesis need to take, before globaloney warmists run up the white flag? According to Albert Einstein, it should only take one:
”To defeat relativity one did not need the word of 100 scientists, just one fact.”
~ A. Einstein
Chris V. (21:01:58) :
…MWP couldn’t have been global- the European warming being offset by Canada and Greenland cooling.
As JAN already pointed out, there was agriculture in Greenland during the MWP, specifically the farming of wheat and flax. The Greenland colony produced a surplus, which was shipped to Northern Europe. Again, these are recorded historical facts…no proxies required.
Today it is too cold in Greenland for wheat and flax to germinate. This is a clear indicator that temperatures were significantly warmer during the MWP globally not just in Europe.
JAN (02:48:07) :
The NAO is a change in atmospheric circulation patterns in the northern hemisphere. If the NAO is warming some area up, then another area is not warming (cooling).
IF the NAO is responsible for the MWP in Europe, that does not support the idea that the MWP was a global event (as the poster who linked to that paper seemed to think- unless I misinterpreted him).
Smokey (04:47:51) :
As is your habit, you’re responding to things I never said.
The NOAA study does just deal with North America, so you can’t extrapolate their conclusions to the rest of the world (as other posters have done).
Smokey et al, your responses do not respond to what I posted.
I guess I’ll assume you guys aren’t very knowledgeable in the science, and have nothing relevant to say.
Chris V.: “As is your habit, you’re responding to things I never said.”
MikeN: “…your responses do not respond to what I posted.”
Are you both nuts??
I quoted what each of you wrote. Verbatim. Word for word. In blockquotes. Then I posted my response to exactly what each of you had said.
You kids need to take an aspirin and lie down. You’re not making sense.
So, Chris, what does that tell you about the hypothesis that the MWP was caused by NAO?
Smokey, the first line of what I posted(not mine but Chris Colose)
‘It should not at all be surprising that CO2 can “lag” planetary temperature changes.’
The second line of your response(and the essence of it)
Yeah, the ‘relationship’ is that rises in CO2 follow temperature rises.
So I’ll ask again. Do you have anything of substance to respond to this statement by Chris Colose?
NOAA says Western Canada has warmed by two degrees and Eastern Canada hasn’t warmed at all because flows of air from naturally shifting Pacific currents have affected the West most.
I n Canada East and West coasts warm up and cool differently because of different factors affect each differently.
It would appear to me that PDO has a greater impact in the western part of Canada and AMO has the greater effect along the east coast whether warming or cooling. The temperatures of each ocean are also different as are the impact of polar jet streams especially during La Nina’s and El Nino’s.
http://facstaff.unca.edu/chennon/classes/atms223/ppt/climatic_oscillations.ppt#298,44,Slide 44
http://facstaff.unca.edu/chennon/classes/atms223/ppt/climatic_oscillations.ppt#297,43,Slide 43
SINCE 2006-2008[after the report]
CANADIAN NATIONAL ANNUAL TEMP ANOAMLIES DROPPED 1.7C
EAST COAST ANNUAL TEMP. ANOMALIES DROPPED 1.1C
NORTH WEST FORESTANNUAL TEMP. ANOMALY DROPPED 2.0C
SINCE 2006-2008[after the report]
CANADIAN NATIONAL WINTER TEMP ANOAMALIES DROPPED 3.6C
EAST COAST WINTER TEMP ANOMALIES DROPPED 1.8C
NORTHWEST WINTER TEMP ANOMALIES DROPPED 7.1C
So all that two degrees of warming is gone in just a couple of years.
JAN (12:38:12) :
So, Chris, what does that tell you about the hypothesis that the MWP was caused by NAO?
You should take that up with the guy who originally posted the link; he said it supported a global MWP. FYI- I haven’t read the paper, only the abstract.
Smokey (12:12:48) :
Are you both nuts??
I can’t speak for Mike, but as for me, no.
All I said is that the NOAA study only covers North America, which is true. I’m not sure what global ice anomalies have to do with that.
Chris V. (14:10:12):
I’m not blaming you for someone else’s opinion here, Chris. My point was only that either:
1. Your understanding of the NAO is incorrect, or
2. The MWP wasn’t caused by the NAO, since the idea of a cooling Canada and Greenland during that period is contradicted by undisputed historical facts.
FYI, I didn’t read the post by Nasif Nahle (07:37:04) as saying the linked paper supported a global MWP, just that the cause of the MWP is now being discussed. A statement the paper does support, in my opinion. If Nasif Nahle meant to say what you imply, I’m sure he can answer for that himself.