NASA Study Finds World Warmth Edging Ancient Levels

NASA GISS ^ | September 26, 2006 | NASA GISS

[cogitator]

A new study by NASA scientists finds that the world's temperature is reaching a level that has not been seen in thousands of years.

The study, led by James Hansen of NASA's Goddard Institute for Space Studies, N.Y., along with scientists from other organizations concludes that, because of a rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels in the current interglacial period, which has lasted nearly 12,000 years. An "interglacial period" is a time in the Earth's history when the area of Earth covered by glaciers was similar or smaller than at the present time. Recent warming is forcing species of plants and animals to move toward the north and south poles.

The study used temperatures around the world taken during the last century. Scientists concluded that these data showed the Earth has been warming at the remarkably rapid rate of approximately 0.36° Fahrenheit (0.2° Celsius) per decade for the past 30 years.

"This evidence implies that we are getting close to dangerous levels of human-made pollution," said Hansen. In recent decades, human-made greenhouse gases have become the largest climate change factor. Greenhouse gases trap heat in the Earth's atmosphere and warm the surface. Some greenhouse gases, which include water vapor, carbon dioxide, methane, nitrous oxide, and ozone, occur naturally, while others are due to human activities.

The study notes that the world's warming is greatest at high latitudes of the Northern Hemisphere, and it is larger over land than over ocean areas. The enhanced warming at high latitudes is attributed to effects of ice and snow. As the Earth warms, snow and ice melt, uncovering darker surfaces that absorb more sunlight and increase warming, a process called a positive feedback. Warming is less over ocean than over land because of the great heat capacity of the deep-mixing ocean, which causes warming to occur more slowly there.

Hansen and his colleagues in New York collaborated with David Lea and Martin Medina-Elizade of UCSB to obtain comparisons of recent temperatures with the history of the Earth over the past million years. The California researchers obtained a record of tropical ocean surface temperatures from the magnesium content in the shells of microscopic sea surface animals, as recorded in ocean sediments.

One of the findings from this collaboration is that the Western Equatorial Pacific and Indian Oceans are now as warm as, or warmer than, at any prior time in the Holocene. The Holocene is the relatively warm period that has existed for almost 12,000 years, since the end of the last major ice age. The Western Pacific and Indian Oceans are important because, as these researchers show, temperature change there is indicative of global temperature change. Therefore, by inference, the world as a whole is now as warm as, or warmer than, at any time in the Holocene.

According to Lea, "The Western Pacific is important for another reason, too: it is a major source of heat for the world's oceans and for the global atmosphere."

In contrast to the Western Pacific, the researchers find that the Eastern Pacific Ocean has not shown an equal magnitude of warming. They explain the lesser warming in the East Pacific Ocean, near South America, as being due to the fact this region is kept cool by upwelling, rising of deeper colder water to shallower depths. The deep ocean layers have not yet been affected much by human-made warming.

Hansen and his colleagues suggest that the increased temperature difference between the Western and Eastern Pacific may boost the likelihood of strong El Ninos, such as those of 1983 and 1998. An El Nino is an event that typically occurs every several years when the warm surface waters in the West Pacific slosh eastward toward South America, in the process altering weather patterns around the world.

The most important result found by these researchers is that the warming in recent decades has brought global temperature to a level within about one degree Celsius (1.8°F) of the maximum temperature of the past million years. According to Hansen, "That means that further global warming of 1 degree Celsius defines a critical level. If warming is kept less than that, effects of global warming may be relatively manageable. During the warmest interglacial periods the Earth was reasonably similar to today. But if further global warming reaches 2 or 3 degrees Celsius, we will likely see changes that make Earth a different planet than the one we know. The last time it was that warm was in the middle Pliocene, about three million years ago, when sea level was estimated to have been about 25 meters (80 feet) higher than today."

Global warming is already beginning to have noticeable effects in nature. Plants and animals can survive only within certain climatic zones, so with the warming of recent decades many of them are beginning to migrate poleward. A study that appeared in Nature Magazine in 2003 found that 1700 plant, animal and insect species moved poleward at an average rate of 6 kilometers (about 4 miles) per decade in the last half of the 20th century.

That migration rate is not fast enough to keep up with the current rate of movement of a given temperature zone, which has reached about 40 kilometers (about 25 miles) per decade in the period 1975 to 2005. "Rapid movement of climatic zones is going to be another stress on wildlife," according to Hansen. "It adds to the stress of habitat loss due to human developments. If we do not slow down the rate of global warming, many species are likely to become extinct. In effect we are pushing them off the planet."

[cogitator]

Because there are already 213 articles on Google News about this, I thought it would be prudent to read the press release FIRST, unfiltered by the media.

The linked press release includes images with captions. I did not include them in this posting.

[cogitator]

** ping **

[BenLurkin]

Exactly.

Thousands of years ago there were no SUVs to blame.

[rhombus]

Scientists concluded that these data showed the Earth has been warming at the remarkably rapid rate of approximately 0.36° Fahrenheit (0.2° Celsius) per decade for the past 30 years.

Oh my God, that's a little over 1 degree in 30 years. I thought it was hot in here. Hey is that a triceratops? Forget about the Muzzies who want to kill us. What are we going to do when the dinosaurs return? Panic now, before it's too late!!!

[ClearCase_guy]

now reaching and passing through the warmest levels in the current interglacial period, which has lasted nearly 12,000 years.

Or, there is this story:

Earth Headed for Warmest Temps in a Million Yearsl

Drive-by climatologists. They just want their name in the paper.

[theBuckwheat]

NASA isn't saying what humans did anciently to mitigate "global warming".

There are plenty of leftists, and supporters of big and Bigger government, and doogooders who are willing to tell us how to mitigate it today. Oddly, nor maybe not so oddly, all their plans have a common thread: reduced liberty, increased costs and increased central control over the lives of the average person.

[DBrow]

"at any prior time in the Holocene"

So things have been getting warmer since the end of the last Ice Age.

Will they get warmer yet as the Milankovitch cycle continues?

[Lucky Dog]

If we do not slow down the rate of global warming, many species are likely to become extinct. In effect we are pushing them off the planet.

Author’s implied logic chain:

Premise: The earth’s climate is becoming warmer than it should from natural processes.
Premise: This warming is the result of human activity.
Conclusion: Changing human activity will stop global warming.

This syllogism is invalid as well as unsound from a number of perspectives. First, the major premise contains an unproven assumption that the current postulated warming is not part of a natural statistical variation. Second, the minor premise is unproven and, hence, the conclusion is potentially false. Third, the conclusion is not inevitable as, even if the second premise were true, it may be too late to reverse any trend or, perhaps, a natural mechanism will mitigate the situation such as a increase in plant life (like algae) to absorb and convert CO2 or other green house gases.

Author’s implied logic chain:

Premise: Global warming is bad.
Premise: Changing human activity will stop global warming.
Conclusion: Prudence demands implementing this change immediately.

This syllogism is also invalid and unsound from a number of perspectives. First, as noted above, there is no concrete indication that global warming will lead to catastrophic or deleterious effects. In fact, ice core drillings have indicated that the earth has been warmer as well as cooler than it is now a number of times in the past without catastrophe. Second, the minor premise is faulty as noted above. Finally, the conclusion ignores the deleterious impacts on humanity of the proposed changes that are speculated to mitigate the problem without the proof that the proposed changes would do anything to lessen global warming.

[NaughtiusMaximus]

The weather is more the way it is today than it has ever been before.

[cynicalman]

Can Someone link me to one or two articles that take the point of view there is no global warming or at least not caused by us humans or SUVs. My daughter is in college and is reading Al Gore's book. I want to send her other points of view. It won't help but a least I will give it a try.

[ClearCase_guy]

These two books are good. If you want articles (more digestible) you could search the net for articles that discuss these books:

"State of Fear" by Michael Crichton
"Skeptical Environmentalist: Measuring the Real State of the World" by Bjorn Lomborg, Bjern Lomberg

[wbill]

A study that appeared in Nature Magazine in 2003 found that 1700 plant, animal and insect species moved poleward at an average rate of 6 kilometers (about 4 miles) per decade in the last half of the 20th century.

So many points to discuss....I'll just pick one.

A specices (as a whole) moved poleward by a total of 20 miles in the past 50 years? How would you go about measuring something like that? And, how would it be relevant?

More Global Warming nonsense. James Hansen, irregardless of his credentials, is one of the larger Chicken Littles out there.

[Parley Baer]

So? We have been comming out of an Ice Age for what 10-12,000 years. It would only be natural for warming to be the highest in thousands of years. If you look at the big picture as I have seen on some graph's this is nothing.

[snowman_returns]

Will they get warmer yet as the Milankovitch cycle continues?

I wonder sometimes whether scientists or eco-warriors have ever heard of The Milankovitch Cycles.

According to the three cycles the northern Hemisphere currently should be due to return to glacial levels, ice core sediments also show that a warming spike was reached just before previous glacial epochs took hold.

[RightWhale]

Heard that NASA guy again this morning pushing his retired-guy agenda. Kind of reminds one of retired guys who appear on the Art Bell Show with their tales of captured UFOs in the mountains.

[palmer]

The most important result found by these researchers is that the warming in recent decades has brought global temperature to a level within about one degree Celsius (1.8°F) of the maximum temperature of the past million years

Also the most misleading result. They are comparing precise measurements from the present with very imprecise and smoothed measurements from the past. All the spikes like the one of the last 30 years disappear when the temperature proxy only takes measurements every century or 1000 years and averages decades or centuries worth of variation into that measurement.

[PissAndVinegar]

yea, but which Bush family member was in office?
And what was Haliburton doing @ the time!?!?

[palmer]

Lots of global warming skeptic links : http://meteo.lcd.lu/globalwarming/

[palmer]

Hansen is supposed to be taken seriously because he converted to global warming alarmist after looking at the data as a skeptical scientist. It's easily seen to be BS when looking at his statements about climate zones moving and stress. He obviously knows nothing about the science, just wants to sound an alarm.