GW: Separating facts from fiction

[a_unique_person]

It's about the only issue the denialists seem to come up with these days. However, as you note, one paper questions one study, while Varwoche has come up with numerous, independent studies from around the world on the issue.

 

[BobK]

We note that there is no evidence that Dr. Mann or any of the other authors in paleoclimatology studies have had significant interactions with mainstream statisticians.

In our further exploration of the social network of authorships in temperature reconstruction, we found that at least 43 authors have direct ties to Dr. Mann by virtue of coauthored papers with him. Our findings from this analysis suggest that authors in the area of paleoclimate studies are closely connected and thus ‘independent studies’ may not be as independent as they might appear on the surface.

Temperature reconstruction are a statistical excercise once data has been accummulated. The idea that there is little or no evidence of interaction with mainstream statisticians by members of the community, is very troubling. You'd think they would want their results verified by those proficient in the statistical field before announcing their findings.

Mann himself told the NRC panel he isn't a statistician. Geologist maybe?

It seems they have concerns about how 'independent' the other multi-proxy studies really are.

We have no reliable history of temperature prior to recording of thermometer readings.

I find it unsurprising temperature has increased since the LIA. We have such a short record, I have seen nothing to worry about. Others are free to do so if they wish. Just don't put a hand in my pocket to assuage the worries of others.

 

[varwoche]

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.

Did they? From the Mann et all 1999 report (pdf):

expanded uncertainties prevent decisive conclusions for the period prior to AD 1400 ... more widespread high-resolution data are needed before more confident conclusions can be reached.

 

[Geckko]

Did they? From the Mann et all 1999 report (pdf):

There does seem to be a little confusion on this matter. For example this was MBH's own press release:

1998 Was Warmest Year of Millennium, UMass Amherst Climate Researchers Report
March 3, 1999

AMHERST, Mass. - Researchers at the University of Massachusetts who study global warming have released a report strongly suggesting that the 1990s were the warmest decade of the millennium, with 1998 the warmest year so far. …

"Temperatures in the latter half of the 20th century were unprecedented," said Bradley. …

Using proxy information gathered by scientists around the world during the past few decades, the team used sophisticated computer analysis and statistics to reconstruct yearly temperatures and their statistical uncertainties, going back to the year AD 1000…

Or this from the IPCC Third assessment report (the one that headlined with the Hockey Stick and for which Mann was a lead author):

Nevertheless the rate and duration of warming of the 20th century has been much greater than in any of the previous nine centuries. Similarly, it is likely that the 1990s have been the warmest decade and 1998 the warmest year of the millennium

IPCC

I think we should all get over this now. The Hockey Stick was extremely poor research and we have wasted a lot of time debating something which should never have seen light of day, possibly because certain egos became inextricably linked to its supposed efficacy.

Now let's deal with the issues at hand.

Move along now.

 

[varwoche]

There does seem to be a little confusion on this matter. For example this was MBH's own press release

I don't see how this contradicts my last cite.

Can you provide a link? And oh, was the emoticon part of the original press release?

Or this from the IPCC Third assessment report (the one that headlined with the Hockey Stick and for which Mann was a lead author)

Ditto (except for the emoticon part. )

Now let's deal with the issues at hand. Move along now.

Er, if you read the OP you may notice that hockey stick IS the original issue at hand.

 

[Geckko]

I don't see how this contradicts my last cite.

Can you provide a link? And oh, was the emoticon part of the original press release?

Ditto (except for the emoticon part. )

Er, if you read the OP you may notice that hockey stick IS the original issue at hand.

The smiley looks wierd doesn't it

Here is the link to the press release:
http://www.umass.edu/newsoffice/newsreleases/articles/12577.php

The link to the IPCC TAR was in my post, just a little inconspicuous.


After so many pages I didn't go back to look at the OP.

I will rephrase. May we now can this debate as irrelevant and distracting.

 

[a_unique_person]

The point, according to scientists, is that the current rate of temperature rise in geological terms is extremely rapid. As more CO2 gets in the atmposphere, it won't get any better.

"If temperatures change slowly, society and the environment have time to adjust," said Mann. "The slow, moderate, long-term cooling trend that we found makes the abrupt warming of the late 20th century even more dramatic. The cooling trend of over 900 years was dramatically reversed in less than a century. The abruptness of the recent warming is key, and it is a potential cause for concern."

 

[a_unique_person]

http://news.bbc.co.uk/1/hi/sci/tech/4783199.stm?ls

The meltdown of Greenland's ice sheet is speeding up, satellite measurements show. Data from a US space agency (Nasa) satellite show that the melting rate has accelerated since 2004.
If the ice cap were to completely disappear, global sea levels would rise by 6.5m (21 feet).
Most of the ice is being lost from eastern Greenland, a US team writes in Science journal.
Jianli Chen of the University of Texas at Austin and colleagues studied monthly changes in the Earth's gravity between April 2002 and November 2005.

It appears the models may be wrong again, and the glacial melt is faster than expected. It should be kept in mind, the scientists will err on the side of caution when making their predictions.

 

[demon]

Oh **** not the "disputed" melting territorries again!
Disputed by just about everyone who doesn`t have a vested interest.

 

[a_unique_person]

http://www.theage.com.au/news/world...limate-timebomb/2006/09/05/1157222131704.html

A CLIMATE change timebomb may be just 10 years away from detonating, according to the latest global warming evidence.
Data from a deep ice core drilled out of the Antarctic permafrost reveals a shocking rate of change in carbon dioxide concentrations. The core, stretching through layers dating back 800,000 years, contains tiny bubbles of ancient air that can be analysed.
Scientists who studied the samples found that they left no doubt as to the extent of the build-up of greenhouse gases. For most of the past 800,000 years, carbon dioxide levels had remained at between 180 and 300 parts per million (ppm) of air. Today they were at 380 ppm.
In the past, it had taken 1000 years for carbon dioxide to rise by 30 ppm during natural warming periods. According to the new measurements, the same level of increase has occurred in the past 17 years.
Isotopic tests confirmed the recent carbon dioxide had come from fossil fuel sources and must be due to human activity.
Eric Wolff, from the British Antarctic Survey, who presented the findings at the BA Festival of Science in Norwich, was alarmed by the rate of change.
"We really are in a situation where something's happening that we don't have any analogue for in our records. It's an experiment we don't know the result of," he said

 

[Darth Rotor]

Oh **** not the "disputed" melting territorries again!
Disputed by just about everyone who doesn`t have a vested interest.

As I understand the Ice Sheet measurement metric, this is an objective measure made by NASA using overhead imagery, and some geosat tools. A similarly measured metric? Watching the water level fall in Lake Meade Behind Hoover Dam. You can see the evidence of water level change.

How can you dispute that the change in the ice pack is from melting? You can argue about the precise cause of the melt, sure, but the melt itself, like the melts in Antarctica, are a matter of objective measurement.

DR

 

[demon]

DR:
"How can you dispute that the change in the ice pack is from melting? You can argue about the precise cause of the melt, sure, but the melt itself, like the melts in Antarctica, are a matter of objective measurement."

I don`t dispute the melting.
I didn`t make a very clear statement there I admit.
It`s been a while since this thread but what I was trying to say was that those who say there is no problem/melting etc have a vested interest and that their positon is disputed by just about everyone who doesn`t have a vested interest.
Guess I was trying to be clever and taking it for granted that I`d been around this forum long enough and people knew where I was coming from on this topic.
Clumsily put again but I hope that clears it up a bit.

 

[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 references anthropogenic warming.

Natl Snow & Ice Data Center 2006.10.04
Arctic ice new

Summers in the Arctic Circle could be ice-free in about 50 years if current melting trends continue

Hadley 2006.10.04
drought new

Drought threatening the lives of millions will spread across half the land surface of the earth

Laboratoire des Sciences du Climat 2006.09.27
methane new agw

the drought that has reduced wetland emissions will end, pumping additional greenhouse gases into the atmosphere as China's own emissions continue to rise

Heliophysics/NCAR 2006.09.13
sunspots new agw

Sunspots alter the amount of energy Earth gets from the sun, but not enough to impact global climate change

U. York 2006.09.07
species extinction new

Between 10 and 99 percent of species will be faced with atmospheric conditions that last existed before they evolved … 10-50 percent of them could disappear

U. Alaska 2006.09.06
permafrost methane new

Global warming is causing Siberian lakes to bubble methane, a greenhouse gas, into the atmosphere at an alarming rate

Potsdam Inst 2006.08.25
ice cores new agw

Ice Age evidence confirms that a doubling of greenhouse gases could drive up world temperatures by about 3 Celsius causing havoc with the climate

FS/Natl Science Foundation 2006.08.16
hurricane intensity new agw

The study shows for the first time a direct relationship between climate change and hurricane intensity

U. Texas 2006.08.11
Greenland ice sheet new

The recent melting rate is significantly larger than before

UCSB 2006.07.21
methane hydrates new

If the world continues to get warmer, vast amounts of methane gas trapped under the sea could belch up and worsen climate change

NOAA/USGS 2006.07.09
ocean acidity 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

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

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

Ohio State 2006.06.27
ice cores

climate system has exceeded a critical threshold

NOAA 2006.06.26
hurricanes 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 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

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

MIT/Penn 2006.05.31
sea temp 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

Rutgers 2005.11.30
sea level new agw

Ocean levels are rising twice as fast today as they were 150 years ago, and human-induced warming appears to be the culprit

Scripps 2005.11.15
water supply 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

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

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

 

[Darth Rotor]

Updated list of sources supporting AGW and/or severity of GW regardless of cause.

There's quote mining, and then there's quote mining. Did you get black lung collecting those tidbits? (teasing)

I liked this one in particular (Russian-Permafrost, as its subject was quite new to me.

In any case, thanks for those links. Some good reads, and some good places to go for interesting stuff.

DR

 

[TheChadd]

lol

 

[lenny]

It appears the models may be wrong again,

all models are wrong.

It should be kept in mind, the scientists will err on the side of caution when making their predictions.

i doubt we understand the models well enough to know which side they will err on; although if your model happens to show a larger response to 2x CO2 than the older models, it will definitely get picked on.