Scientists: Humans the main culprit in global warming

Scripps Howard News Service | December 16, 2002 | JOAN LOWY

[new cruelty]

- With 2002 on track to be the second-warmest year on record, scientists said Monday they are confident that human activity, rather than a natural variation in Earth's climate, is responsible for the unprecedented warming trend of the past two decades.

Global data from NASA's Goddard Institute for Space Studies shows that the first 11 months of 2002 averaged 58.37 degrees F, just under the record high of 58.44 degrees set in 1998. Goddard director James Hansen said he is confident that the trend will hold true through the end of this month as well.

The 16 warmest years since record-keeping began in 1880 have all occurred since 1980. Last year was the second-warmest, but now drops to third.

Indeed, studies show that 1998 and 2002 are the two warmest years in the Northern Hemisphere in at least the last 1,000 years, said University of Virginia climatologist Michael Mann.

The estimate is based on both human record-keeping and physical records like ice cores, tree rings and coral, Mann said. A similar estimate has not been made for the Southern Hemisphere due to gaps in available data, he said.

Scientists had thought the record temperatures of the past two decades might be attributable to a natural, temporary warm spell. But the persistent increase in warming has "now taken us to a level that is well outside natural variability," Hansen said. "It is now clear that human (activity) has become dominant over the natural variability."

The human activity chiefly responsible for warming is the emission of carbon dioxide through the burning of fossil fuels like oil, coal and gas, scientists believe. Concentrations of carbon dioxide in the atmosphere have increased more than 30 percent since the start of the industrial revolution 200 years ago, with most of the increase occurring in the last 50 years.

Some scientists had argued that the warming trend of recent decades was comparable to a period of unusual warmth in the 1930s and 1940s, and thus might be the result primarily of natural fluctuations in Earth's climate. But the record warmth of the 1990s and early 21st century "go well beyond" previous periods of warm temperatures, Hansen said.

The average global temperature for January 2002 was 58.49 degrees, the highest of any January on record. March temperatures were the highest of any March on record. And from April through November, each month was either the second-, third- or fourth-warmest for its month on record.

Some scientists have questioned whether 1998's record warmth can be attributed primarily to global warming since it occurred in an El Nino year. El Nino is a disruption of the ocean-atmosphere system in the tropical Pacific associated with increased rain and warm temperatures around the globe.

But there is no El Nino this year and 2002 temperatures are nearly as high as those of 1998, Mann noted.

"It seems obvious just to the lay person that if we're getting these record breakers almost every year something unusual is going on that doesn't just result from a random rolling of the dice," Mann said. "It suggests we're moving well beyond the envelope of variability of climate that we've seen in the past into levels of warmth that just doesn't happen naturally."

On the Net: Goddard Institute for Space Studies - www.giss.nasa.gov/research/observe/surftemp/

[Congressman Billybob]

This article is a classic example of junk science. It is total bullsh*t, unless the reporter asks and answers the question, "How hot was the Sun in 2002?" I deal with this precise subject in my latest column for UPI, which I submitted a day early because of this article.

Click the first link below for "Junk Science - Harvard and Beyond" as I submitted it to UPI, minutes ago.

Congressman Billybob

Click for latest column on UPI, "Junk Science - Harvard and Beyond" (Not yet on UPI wire, nor FR.)

Click for latest book, "to Restore Trust in America"

[tracer]

And here I thought that the wrens were to blame.....

[itsahoot]

These clowns actually put a lot of people in jail based on their scientific, expert testimony.

[Reeses]

then we can begin to have a debate about whether or not there is warming.

If we agree with them that there is warming then we can lay them off, their work is done. After spending $100 billion on scientists to detect a 0.1 degree increase enough is enough. I'd rather spend future money on a) what temperature do we want? and b) what technologies can we use to set that temperature? A Luddite approach to our environment is silly. It could be we should be giving tax breaks to factories to produce more CO2, not less.

[JasonC]

Anybody else notice the rather silly side by side comparison of a mean temperature for an entire year, with a a mean temperature for a year -except- December? That is what the 2002 claim is made about.

If it were really on track to break records, they would have waited until January 1 and made a statement about the full year average. Instead, when it was clear it wasn't going to be a record, they effectively threw out a cold month (December) and just pretend that it is apples to apples to compare January through November 2002 to January through December in some other year.

Hansen gets more and more a pure media spin "shill", without any scientific standards, as time goes on...

[rustbucket]

Is Mann ignorant, or is he lying?

Good question. Here's the latest from NOAA: Current El Nino.

From that NOAA site: “This is a classic El Niño pattern,” said retired U.S. Navy Vice Admiral Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator.

[GOP_1900AD]

Here in near coastal N. Calif we are still waiting for a truly warm summer or a reasonably warm fall, like the ones we last experienced during the mid to late 1980s. Warming? Hah!

[GOP_1900AD]

Lying. There is a mild El Nino at present. Not much of one though. We have gotten quite a bit of rain in the past week here in N. Calif. But it's not as warm overall as it would be with a full strength El Nino. Had a warmish (but still below what I consider normal - of course, now that we have not had any real consistent summer / fall warmth since the late 80s, "normal" is now biased!) fall and yet another cool summer, with very few days above 90. Away from the coastal fog.

[rustbucket]

Mann is the person who reconstructed a global temperature record for the last millennium that showed relatively little impact of the Maunder Minimum "Little Ice Age" and the Medieval Warm Period.

The UN's Intergovernmental Panel on Climate Change (IPCC) used Mann's "hockey stick" global temperature reconstruction as the basis of their investigation into climate change. If one assumes a temperature record like Mann's that is relatively flat or slightly declining except for the last 100 years or so, then the only explanation for the last century's rise in temperature becomes the human influence.

Other scientists do not agree with Mann's temperature reconstruction: Temperature Record.

The Little Ice Age was clearly global in its extent. I've been following scientific papers on it for years, and I about fell out of my chair when I saw what the IPCC had used.

[ancient_geezer]

"It is now clear that human (activity) has become dominant over the natural variability."

Sure, and I have some ocean front property in Colorado tah sell yah.

 

Globally Averaged Atmospheric Temperatures
(NASA)

This chart shows the monthly temperature changes for the lower troposphere - Earth's atmosphere from the surface to 8 km, or 5 miles up. The temperature in this region is more strongly influenced by oceanic activity, particularly the "El Niño" and "La Niña" phenomena, which originate as changes in oceanic and atmospheric circulations in the tropical Pacific Ocean. The overall trend in the tropospheric data is near zero, being +0.04 C/decade through Feb 2002. Click on the chart to get the numerical data.

Ice Ages & Astronomical Causes
Brief Introduction to the History of Climate
by Richard A. Muller

Figure 1-1 Global warming

Figure 1-2 Climate of the last 2400 years

 

Figure 1-3 Climate of the last 12,000 years

Figure 1-4 Climate of the last 100,000 years

Figure 1-5 Climate for the last 420 kyr, from Vostok ice