GW: Separating facts from fiction

[a_unique_person]

Not sure if it's been mentioned in this thread or elsewhere. A cursory search brings up nothing.

http://www.sciam.com/article.cfm?chanID=sa006&colID=13&articleID=000B557A-71ED-146C-ADB783414B7F0000

Nevertheless, data trump politics, and a convergence of evidence from numerous sources has led me to make a cognitive switch on the subject of anthropogenic global warming...

Al Gore delivered the single finest summation of the evidence for global warming I have ever heard...

Because of the complexity of the problem, environmental skepticism was once tenable. No longer. It is time to flip from skepticism to activism.

And biologist Tim Flannery's The Weather Makers (Atlantic Monthly Press, 2006) reveals how he went from being a skeptical environmentalist to a believing activist as incontrovertible data linking the increase of carbon dioxide to global warming accumulated in the past decade.

Read it. An excellent book. My scientist friend does not believe runaway is likely, given that the past has seen higher levels of CO2. He does believe AGW is real and will have to be dealt with.

 

[varwoche]

Updated list of sources supporting AGW and/or severity of GW regardless of cause. new indicates the study is newly added to the list. agw indicates the study supports anthropogenic warming.

Australia Environment Dept 2006.05.23
meta study new

greater risk that global warming could now exceed previous predictions of a 1.4 to 5.8 degrees Celsius rise in temperatures by the year 2100

UC Berkeley 2006.05.22
Antarctic ice cores new agw

temperatures by the end of the century will be even hotter than current climate models predict

WU/PI/CEH 2006.05.22
polar ice cores new agw

estimates for the next century may have substantially underestimated the potential magnitude of global warming

NOAA 2006.05.03
Pacific wind circulation agw

Global warming caused by human activity has begun to dampen an important wind circulation pattern over the Pacific Ocean

U.S. Climate Change Science Program 2006.05.02
atmosphere temp agw

A nagging difference in temperature readings that had raised questions about global warming has been resolved … The findings show clear evidence of human influences on climate

China National Meteorological Bureau 2006.05.02
glaciers

Glaciers covering China's Qinghai-Tibet plateau are shrinking by 7 percent a year due to global warming

National Center for Atmospheric Research 2006.04.12
hurricanes agw

The hurricanes we are seeing are indeed a direct result of climate change ... increasingly due to greenhouse gases.

University of Minnesota 2006.04.12
plants/CO2 agw

Plants won't suck up as much of the carbon dioxide contributing to global warming as scientists had hoped … worldwide computer modeling counted on plants to absorb a good share of the extra carbon dioxide

British Antarctic Survey 2006.03.31
Antarctica temp

A new analysis of the past 30 years of records from nine research stations ... reveals that the air above the entirety of Antarctica has warmed by as much as 0.70 degree Celsius per decade during the winter months.

University of Arizona 2006.03.23
glaciers

Water from melting ice sheets and glaciers is gushing into the world's oceans much faster than previously thought possible ... The unexpected deluge is raising global sea levels

NASA 2006.03.14
Arctic temp / smog agw

NASA scientists have found that a major form of global air pollution involved in summertime ""smog"" has also played a significant role in warming the Arctic

NASA/GRACE 2006.03.02
Antarctica shrinking

Antarctica's ice sheet lost a significant amount of mass since the launch of GRACE in 2002. The estimated mass loss was enough to raise global sea level about 1.2 millimeters

Woods Hole 2006.02.17
Atlantic temp

Study Suggests Climate Models Underestimate Future Warming

Yale/NOAA 2006.02.28
atmosphere temp

Unfortunately, the warming is in an accelerating trend

UCSC 2006.02.28
greenhouse gas emmision rate agw

Human activities are releasing greenhouse gases more than 30 times faster than the rate of emissions that triggered a period of extreme global warming in the Earth's past

NOAA 2006.02.03
Arctic shrinking

Arctic sea ice has decreased between 1973 and 1996 at a rate of -2.8 +/- 0.3%/decade ... the projected change of 3 to 7°F (1.5 - 4°C) over the next century would be unprecedented

Scripps/DOE 2006.01.26
Arctic shrinking agw

Enhanced aerosol concentrations increase the amount of thermal energy emitted by many Arctic clouds... The Arctic is showing the first unmistakable signs of climate warming caused by human activities, in the form of rapidly retreating and thinning sea ice

Bjerknes 2006.01.18
greenhouse gas levels new

Current levels of the greenhouse gases, carbon dioxide and methane, are higher now than they have ever been in 650 000 years

US Global Climate Change Office 2005.11.09
opinion agw

It is becoming clear that human activities, mainly burning fossil fuels and deforestation, are part of the cause of this warming.

Hadley 2005.12.21
effect of aeresols new agw

New observations show that man-made aerosols may be having a greater direct effect on our climate than previously thought

BAS/USGS 2005.04.21
glacier retreat

over the last 50 years 87% of 244 glaciers studied have retreated, and that average retreat rates have accelerated

Scripps/Livermore 2005.02.17
ocean temp agw

results clearly indicate that the warming is produced anthropogenically ... The statistical significance of these results is far too strong to be merely dismissed and should wipe out much of the uncertainty about the reality of global warming.

Ohio State 2005.01.30
Kilamanjaro melting

the ice fields capping the mountain would disappear between 2015 and 2020, the victims, at least in part, of global warming ... the rate of ice loss may even be accelerating.

Hadley 2004.11.18
surface temp new agw

large-scale global warming is not a result of urban development

Schneider/Stanford 2004.09.30
opinion agw

the vast majority of knowledgeable climate scientists have said that despite the remaining uncertainties, that it's very likely (more than 90%), that humans are least part of the story

NASA 2003.10.23
Arctic temps, ice cover

twenty-year record of space based measurements has been analyzed by researchers at NASA's Goddard Space Flight Center. Based on their findings, evidence of a warming planet continues to grow

IPCC 2001.12.31
meta study agw

Emmissions of greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to alter the climate

NOAA/GFDL 2001.04.30
ocean temp new agw

The ocean has become warmer in the last 50 years and that warming is likely due to human-induced causes

DOE/Livermore/Santer 2001.03.31
aerosols, greenhouse gases agw

identified the anthropogenic ""fingerprint"" of climate change ... hard evidence that human activities have global-scale consequences

McCarthy/Harvard 2001.03.22
opinion agw

coordinated a remarkable report by the world scientific community this year that said global warming is real, it's here, and it's going to be worse than we thought ... evidence is overwhelming that humans are causing most of the change

EPA 2000.01.07
opinion agw

There is no doubt this atmospheric buildup of carbon dioxide and other greenhouse gases is largely the result of human activities ... In short, scientists think rising levels of greenhouse gases in the atmosphere are contributing to global warming

PEW Center for Climate Change
opinion agw

greenhouse gases appear to be the dominant driver of climate change over the past few decades

 

[varwoche]

A new report from the National Academy of Sciences supports the Mann hockey stick, further refuting M&M.

Their conclusions were meant to address, and they lent credibility to, a well-known graphic among climate researchers - a "hockey-stick" chart that climate scientists Michael Mann, Raymond Bradley and Malcolm Hughes created in the late 1990s to show the Northern Hemisphere was the warmest it has been in 2,000 years.

article

 

[BobK]

Here's the NRC report, news release, and press conference.
Full Report
News Release
Opening Statement
Report Briefs
Listen to webcast of press conference .rm RealPlayer file
Download of webcast 63meg .mpg file

What I got concerning the hockeystick, is that they shortened their confidence in it by 60% of it's length, to only the last 400 years. Sometime during the little ice age. Hardly surprising temps have gone up.

What do you get when you shorten a hockeystick by 60%? A boomerang?

Judge for yourself whether they should do more research before instituting an expensive global policy. That may, or may not benefit imaginary people of the future.

 

[RandFan]

randfan is spot on-- the argument is most certainly circular!-- it may not have any consequences on the conclusion, BUT it is completely justified to ask of proper logic in a skeptic forum.

Light shines in a dark world of fallacious reasoning.

 

[varwoche]

Here's the NRC report, news release, and press conference.
Full Report
News Release
Opening Statement
Report Briefs
Listen to webcast of press conference .rm RealPlayer file
Download of webcast 63meg .mpg file

Thanks.

From the opening statement:

Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900.

Note that 900 was the start of the midevil warm period -- the period of time central to M&M's analysis. Also note that despite that confidence levels in the reconstructions diminish with time -- as I would expect -- that he goes on to say:

The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on icecaps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years.

 

[DavidJames]

That may, or may not benefit imaginary people of the future.

Imaginary people?

 

[BobK]

From the opening statement.

Let me summarize five key conclusions we reached after reviewing the evidence:

1. The instrumentally measured warming of about 0.6°C during the 20th century is also reflected in borehole temperature measurements, the retreat of glaciers, and other observational evidence, and can be simulated with climate models.

2. Large-scale surface temperature reconstructions yield a generally consistent picture of temperature trends during the preceding millennium, including relatively warm conditions centered around A.D. 1000 (identified by some as the "Medieval Warm Period") and a relatively cold period (or "Little Ice Age") centered around 1700.

3. It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies.

4. Less confidence can be placed in large-scale surface temperature reconstructions for the period A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900. The uncertainties increase substantially backward in time through this period and are not yet fully quantified.

5. Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900.

3, 4, 5, indicate an erosion of confidence prior to 1600. So, to claim "highest temps in 1000 years" cannot be supported by the current evidence.

Here's the headline from this article.

Earth Hottest It's Been in 2,000 Years

Anyone here think that isn't media scare-mongering?

 

[BobK]

Imaginary people?

I call them imaginary since we only think/hope they will exist. We can never know. They exist only in our minds.

Just trying to get across this point. Since so many real unfortunates are dying from lack of clean water and food, it doesn't make much sense to expend resources on the imaginary people of the future. First, get our own house in order.

I think the lives of real people are more important than the lives of the imaginary.

 

[DavidJames]

I call them imaginary since we only think/hope they will exist. We can never know. They exist only in our minds.

Just trying to get across this point. Since so many real unfortunates are dying from lack of clean water and food, it doesn't make much sense to expend resources on the imaginary people of the future. First, get our own house in order.

I think the lives of real people are more important than the lives of the imaginary.

I think that may be a bit of a false dichotomy. Plus, rather then "hoping" they exist, I have no problems with taking some steps to improve their chances.

 

[lenny]

Here's the headline from this article.
Anyone here think that isn't media scare-mongering?

no, not really. what do you think "the media" wants more: to scare monger or to gain a larger market share? the guys who write the headlines are often specialists: they produce hooks: you bite, they score. (i do not deny that this may well have other negative effects, but i took your comment to imply intent). you bit.

if you read the forbes article itself:

It said the "recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia,"

in the fourth paragraph, and later:

The academy panel said it had less confidence in the evidence of temperatures before 1600. But it considered the evidence reliable enough to conclude...

the article appears better than most to me, it makes it easy to find the academy report itself, and the web sites of the main players. i have had my own work twisted much worse to yield a "better story". (i was upset the first time but once you accept that their aim is not to educate but to increase sales, then you (i) have to admit that it is irrational to expect them to behaive otherwise.)
in terms of your specifics doubts:

3, 4, 5, indicate an erosion of confidence prior to 1600. So, to claim "highest temps in 1000 years" cannot be supported by the current evidence.

not quite.

3 states that we have a high level of confidence inthe last 400 years; we can erode a long way from high confidence and still claim evidence.
4 states the (obvious when you think about it) fact that it is harder to interpret/calibrate temperature before the thermometer was invented (and europeans carried it around the globe). still "reliable enough to conclude..."
5 admits that we have little confidence in hemispheric means prior to 900 AD, but then that is already outside your "1000 years"; never-the-less one can make consistency arguments, even if when we cannot make confident averages (i've ordered the original NAS report, but not read it yet; i suspect they do just that prior to 900).

so i'd say the article was better than most (factual, sources well-documented, with no trace of scare mongering) and that the headline did exactly what it was designed to do.

no?

 

[CapelDodger]

I call them imaginary since we only think/hope they will exist. We can never know. They exist only in our minds.

But we might as well assume that they will exist. Especially those of us who like the prospect of grandchildren. (Which doesn't include me, by the way. But I'd like my nepots' children to live in not-too-interesting times.)

Just trying to get across this point. Since so many real unfortunates are dying from lack of clean water and food, it doesn't make much sense to expend resources on the imaginary people of the future. First, get our own house in order.

Firstly, it's not as if there's a fund that could be spent this way, or could be spent that way. The money that's not being spent on reducing global warming isn't being spent on true unfortunates. It's being spent on fripperies - bigger cars, more electronic gizmos, male grooming products, weapons, weapons, weapons ...

Secondly, never reinforce defeat. If we have to sacrifice the poor of today, in favour of people a few generations down the line who won't be there if we don't, so be it.

I think the lives of real people are more important than the lives of the imaginary.

Real people tend to have some concern for their grandchildren, even in prospect. It's an important part of their lives. There's 6-odd billion people on this planet, and most live along rivers that have their source in Tibetan glaciers. That's where the majority has always lived since agriculture first complicated matters. If you want to concentrate on real people, Tibetan ice is the first priority. Forget AIDS in Africa, forget Africa, it's what, 300 million excluding the Nile? Fewer? As many real people as that depend on the Ganges.

 

[CapelDodger]

I think that may be a bit of a false dichotomy. Plus, rather then "hoping" they exist, I have no problems with taking some steps to improve their chances.

I think in terms of some pimply youth 20 years down the line pointing the finger at me and my generation for his problems. I'm not answerable for my generation - whatever that might be - but I'm answerable for me. And I'd like to have a crushing response, which I'm working on.

 

[CapelDodger]

The guys who write the headlines are often specialists ...

They're called "subs", which undeniably derives from sub-editor. Not from substantial. Sub many other things, by various accounts. There's also a verb, "subbing", which is akin to rape. By some accounts. That's when they don't just scan the piece and whack on a hooky title but actually edit it to fit the hooky title. Or the space available.

What's a sub-machine-gun for? Yeah, you got it.

 

[a_unique_person]

I call them imaginary since we only think/hope they will exist. We can never know. They exist only in our minds.

Just trying to get across this point. Since so many real unfortunates are dying from lack of clean water and food, it doesn't make much sense to expend resources on the imaginary people of the future. First, get our own house in order.

I think the lives of real people are more important than the lives of the imaginary.

That's a false dichotomey invented by the 'skeptical' environmentalist. There is nothing to stop us improving water and food and looking after the evironment at the same time.

 

[varwoche]

Updated list of sources supporting AGW and/or severity of GW regardless of cause. new indicates the study is newly added to the list. agw indicates the study supports anthropogenic warming.

NOAA/USGS 2006.07.09
ocean acidity new agw

It is clear that seawater chemistry will change in coming decades and centuries in ways that will dramatically alter marine life

Scripps/UA 2006.07.06
forest fires new

The increase in the number of large western wildfires in recent years may be a result of global warming

Univ. of Illinios 2006.06.29
crop yield new

increase in crop yields due to the buildup of greenhouse gases would be modest or nonexistent

Ohio State 2006.06.27
ice cores new

climate system has exceeded a critical threshold

NOAA 2006.06.26
hurricanes new agw

Global warming provided much of the ocean heat that fueled last year's record-setting hurricane season

Natl Academy of Sciences 2006.06.22
meta study new agw

recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia

Russian Academy of Science 2006.06.15
permafrost new

permafrost traps far more carbon than previously thought … The reservoir is very large and dangerous

MIT/Penn 2006.05.31
sea temp new agw

Anthropogenic factors are likely responsible for long-term trends in tropical Atlantic warmth and tropical cyclone activity

Australia Environment Dept 2006.05.23
meta study

greater risk that global warming could now exceed previous predictions of a 1.4 to 5.8 degrees Celsius rise in temperatures by the year 2100

UC Berkeley 2006.05.22
Antarctic ice cores agw

temperatures by the end of the century will be even hotter than current climate models predict

WU/PI/CEH 2006.05.22
polar ice cores agw

estimates for the next century may have substantially underestimated the potential magnitude of global warming

NOAA 2006.05.03
Pacific wind circulation agw

Global warming caused by human activity has begun to dampen an important wind circulation pattern over the Pacific Ocean

U.S. Climate Change Science Program 2006.05.02
atmosphere temp agw

there is no longer a discrepancy in the rate of global average temperature increase for the surface compared with higher levels in the atmosphere … The evidence continues to support a substantial human impact

China National Meteorological Bureau 2006.05.02
glaciers

Glaciers covering China's Qinghai-Tibet plateau are shrinking by 7 percent a year due to global warming

National Center for Atmospheric Research 2006.04.25
hurricanes

because of warmer sea-surface temperatures and moister air, more energy goes into the showers and thunderstorms that feed hurricanes

University of Minnesota 2006.04.12
plants/CO2 agw

Plants won't suck up as much of the carbon dioxide contributing to global warming as scientists had hoped … worldwide computer modeling counted on plants to absorb a good share of the extra carbon dioxide

British Antarctic Survey 2006.03.31
Antarctica temp

A new analysis of the past 30 years of records from nine research stations ... reveals that the air above the entirety of Antarctica has warmed by as much as 0.70 degree Celsius per decade during the winter months.

University of Arizona 2006.03.23
glaciers

Water from melting ice sheets and glaciers is gushing into the world's oceans much faster than previously thought possible ... The unexpected deluge is raising global sea levels

NASA 2006.03.14
Arctic temp / smog agw

NASA scientists have found that a major form of global air pollution involved in summertime ""smog"" has also played a significant role in warming the Arctic

NASA/GRACE 2006.03.02
Antarctica shrinking

Antarctica's ice sheet lost a significant amount of mass since the launch of GRACE in 2002. The estimated mass loss was enough to raise global sea level about 1.2 millimeters

Woods Hole 2006.02.17
Atlantic temp

Study Suggests Climate Models Underestimate Future Warming

Yale/NOAA 2006.02.28
atmosphere temp

Unfortunately, the warming is in an accelerating trend

UCSC 2006.02.28
greenhouse gas emmision rate agw

Human activities are releasing greenhouse gases more than 30 times faster than the rate of emissions that triggered a period of extreme global warming in the Earth's past

NOAA 2006.02.03
Arctic shrinking

Arctic sea ice has decreased between 1973 and 1996 at a rate of -2.8 +/- 0.3%/decade ... the projected change of 3 to 7°F (1.5 - 4°C) over the next century would be unprecedented

Scripps/DOE 2006.01.26
Arctic shrinking agw

Enhanced aerosol concentrations increase the amount of thermal energy emitted by many Arctic clouds... The Arctic is showing the first unmistakable signs of climate warming caused by human activities, in the form of rapidly retreating and thinning sea ice

Bjerknes 2006.01.18
greenhouse gas levels

Current levels of the greenhouse gases, carbon dioxide and methane, are higher now than they have ever been in 650 000 years

US Global Climate Change Office 2005.11.09
opinion agw

It is becoming clear that human activities, mainly burning fossil fuels and deforestation, are part of the cause of this warming.

Hadley 2005.12.21
effect of aeresols agw

New observations show that man-made aerosols may be having a greater direct effect on our climate than previously thought

Scripps 2005.11.15
water supply new agw

global warming will reduce glaciers and storage packs of snow in regions around the world, causing water shortages and other problems that will impact millions of people

BAS/USGS 2005.04.21
glacier retreat

over the last 50 years 87% of 244 glaciers studied have retreated, and that average retreat rates have accelerated

Scripps/Livermore 2005.02.17
ocean temp agw

results clearly indicate that the warming is produced anthropogenically ... The statistical significance of these results is far too strong to be merely dismissed and should wipe out much of the uncertainty about the reality of global warming.

Ohio State 2005.01.30
Kilamanjaro melting

the ice fields capping the mountain would disappear between 2015 and 2020, the victims, at least in part, of global warming ... the rate of ice loss may even be accelerating.

Hadley 2004.11.18
surface temp agw

large-scale global warming is not a result of urban development

Schneider/Stanford 2004.09.30
opinion agw

the vast majority of knowledgeable climate scientists have said that despite the remaining uncertainties, that it's very likely (more than 90%), that humans are least part of the story

NASA 2003.10.23
Arctic temps, ice cover

twenty-year record of space based measurements has been analyzed by researchers at NASA's Goddard Space Flight Center. Based on their findings, evidence of a warming planet continues to grow

IPCC 2001.12.31
meta study agw

Emmissions of greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to alter the climate

NOAA/GFDL 2001.04.30
ocean temp agw

The ocean has become warmer in the last 50 years and that warming is likely due to human-induced causes

DOE/Livermore/Santer 2001.03.31
aerosols, greenhouse gases agw

identified the anthropogenic ""fingerprint"" of climate change ... hard evidence that human activities have global-scale consequences

McCarthy/Harvard 2001.03.22
opinion agw

coordinated a remarkable report by the world scientific community this year that said global warming is real, it's here, and it's going to be worse than we thought ... evidence is overwhelming that humans are causing most of the change

EPA 2000.01.07
opinion agw

There is no doubt this atmospheric buildup of carbon dioxide and other greenhouse gases is largely the result of human activities ... In short, scientists think rising levels of greenhouse gases in the atmosphere are contributing to global warming

PEW Center for Climate Change
opinion agw

greenhouse gases appear to be the dominant driver of climate change over the past few decades

 

[a_unique_person]

More evidence. Thanks.

 

[BobK]

Just out. An analysis of Mann's hockeystick work. Done by 3 eminent statisticians unconnected to either Mann or M&M, and done for no remuneration.

A 90k .pdf Fact sheet
Comment #2 here is Mann's response

1.5 meg .pdf Entire report
Much more verbose and includes a social network analysis of the paleoclimate research community. Demonstrates why many other studies should not be considered independent.

What was striking to me is the clarity of their presentation. I found it to be short on weasel wording. Not math heavy. I expect most people will be able to follow it.

 

[a_unique_person]

Just out. An analysis of Mann's hockeystick work. Done by 3 eminent statisticians unconnected to either Mann or M&M, and done for no remuneration.

A 90k .pdf Fact sheet
Comment #2 here is Mann's response

1.5 meg .pdf Entire report
Much more verbose and includes a social network analysis of the paleoclimate research community. Demonstrates why many other studies should not be considered independent.

What was striking to me is the clarity of their presentation. I found it to be short on weasel wording. Not math heavy. I expect most people will be able to follow it.

Mann says.

Barton's report also reveals that his panel collaborated closely with the two Canadians, yet made no attempt to contact me or my collaborators at any point.

Why would they do that?

Apart from that, M&M is not the case for AGW. The evidence is all around us, right now, and is being reported on in a scientific manner by scientists.

The report is not put out by any of the scientific bodies that Varwoche posts references to, but is being published by the House Comitte of Energy and Commerce.

 

[BobK]

Mann says.



Why would they do that?

Apart from that, M&M is not the case for AGW. The evidence is all around us, right now, and is being reported on in a scientific manner by scientists.

The report is not put out by any of the scientific bodies that Varwoche posts references to, but is being published by the House Comitte of Energy and Commerce.

What's your point? Other than you seem to disapprove of their study.

I thought we were putting links to various climate related studies in this thread for people to read for themselves.

I didn't even mention M&M. But since you brought them up. I see the statisticians are supportive of M&M's conclusions.