Global Warming : [On the nasa.gov web site, dated June 3, 2010]
Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century primarily due to the greenhouse gases released by people burning fossil fuels.Tom Nelson: [So how can the 20th century warming be spun as more rapid than this 18th century warming?]
How Does Today’s Warming Compare to Past Climate Change?
Earth has experienced climate change in the past without help from humanity. But the current climatic warming is occurring much more rapidly than past warming events.
Why Do Scientists Think Current Warming Isn’t Natural?
In Earth’s history before the Industrial Revolution, Earth’s climate changed due to natural causes unrelated to human activity. These natural causes are still in play today, but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades.
[David Archibald] What is also interesting is the 2.2° temperature rise from 7.8° in 1696 to 10.0° in 1732. This is a 2.2° rise is 36 years [in Central England]. By comparison, the world has seen a 0.6° rise over the 100 years of the 20th century. That temperature rise in the early 18th century was four times as large and three times as fast as the rise in the 20th century.
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7 comments:
Comparing a regional rate of change ("Central England") to a global rate of change obviously proves nothing.
Great David, I guess this qualifies to be in the next IPCC report! Because as you said, it proves nothing, perfect fit.
The Medieval Warm Period was warmer than today and it warmed faster and through totally natural input. So today the cooler slower to warm times are so because of human input?
I do not think so. There are other factors like Svensmark's theory of sunspots and low cloud cover for one. Discount GHG warming, this does not exist. And do not throw Venus back at me, there the heat is because Venus is closer to the sun, the heavy thick atmosphere heats through adiabatic compression and there is no water.
What is also interesting is the 1.32°F (0.73°C) temperature rise from 1790 to 1847 in 57 years in the Philadelphia, Pennsylvania area. This is double the rate of the 0.6°C global temperature rise of the 20th century.
(Source: A Meteorological Account of the Weather in Philadelphia from January 1, 1790 to January 1, 1847 by Charles Peirce.
Straight line linear regression of annual mean temperature data. Excludes year 1816 "The Year without Summer" caused by the Tambora volcanic eruption.)
What is interesting or relevant about the warming of a single location (Philadelphia) compared to changes in global averages?
Svensmark's theory has little-to-no validity beyond Svensmark's opinion, as at least two articles in Science magazine over the past 2 yrs have demonstrated.
John Marshall wrote:
> The Medieval Warm Period
> was warmer than today and it
> warmed faster and through totally
> natural input.
The MWP was not warmer than today according to most studies, nor was it global.
In any case, it does not matter, as today's climate is a result of forcings that did not exist 1000 yrs ago. We're in a *completely* different environment now. It is the consequences of these new, additional forcings that is interesting and relevant, not merely whether temperatures today are higher then temperatures then. Even more important is the temperatures of the next 100 yrs, and the dominant (additional) forcings today are manmade, not natural.
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