Re: Global Warming General Thread
Posted: Wed Aug 31, 2011 12:16 am
Excellent comments from a person on Huff Po:
***
"How much warmer seems good for you? 1 degree, 3 degrees? 10?
I.e., we have indirect evidence that ~40 million years ago, atmospheric CO2 levels were comparable to now, along with elevated temperatures.
http://www.sciencemag.org/content ... .abstract
But for CO2 levels comparable to what's projected for later this century (500 - 650ppmv), global average temperatures eventually rose by as much 29 degs F higher.
Think you'll like another 29 degrees F hotter? How about your great great grand kids? Think they'll agree with you?
Well, OK. Maybe you don't care about your distant progeny. Fair enough. But some of us do.
http://www2.ucar.edu/news/3628/ea ... e-climate”
***
Even with overwhelming evidence, scientific theories can't proven; only disproven. But good theories stand the test of time; bad theories are inconsistent with evidence. E.g., volcanoes emit less than 1% the CO2 that fossil fuel burning does. Earth orbital changes take many thousands of years. Our global warming is happening w/i 200 years. Sunshine is in a lull. So, forget those explanations.
However, multiple methods show
1) CO2 is a greenhouse gas, which has increased 40% since 1850 when humans started burning fossil fuels BIG.
2) Human CO2 production has exceeded (currently double) its global rise rate since 1850. This says that human causes are large enough to impact CO2 levels and that Earth incompletely absorbs excess CO2 production.
3) As a greenhouse gas, temperature rises provoked by excess CO2 also increases water vapor, which is also a greenhouse gas. Measurements show this is happening.
4) So, rising CO2 induces rising temperature due to both itself and increased water vapor.
5) Dead plant/animal material stops absorbing new carbon. So the radioactive carbon in it decays, changing its carbon isotope ratio. When changed carbon gets dug up and burned after millions of years, it changes atmospheric CO2. isotope ratio. Those changes are consistent with excess CO2 from burning fossil fuels. That fingerprint's the clincher.
6) All other accounts fail the evidence.
***
Antarctic ice core data verifies the 40% increased CO2 figure. CO2 is well-mixed world wide. So, Antarctic sampling is representative of the rest of the globe and it's very clean - no contamination. Atmospheric gases get embedded as microscopic air bubbles w/i snow, which gets compressed to ice by later snowfall. It snows more in winter. So, you see yearly rings, like tree rings. So, these ice core samples from Epica and Vostok trace very slight yearly changes in atmospheric gas composition, as far back as 780,000 years.
'
Quite a feat, eh? Not for wimps.
However, since ~1957, there's direct CO2 measurements from Mauna Loa Observatory, starting with Charles Keeling's first 10 year data set, which I viewed in 1968. I think that first set was around 320 - 330 parts per million by volume (ppmv).
It also showed the expected seasonal CO2 dip in the northern hemisphere's summer, but with an even stronger climb during northern hemisphere winter. This happens because most of the Earth's land masses and thus vegetation is in the northern hemisphere. (Oceanic plankton counts for less.) And photosynthesis (which removes CO2) is stronger in summer when plants have leaves. Plants mostly respire (give off CO2) in winter. Animals of course always respire, as they don't photosynthesize.
Despite seasonal sawtooth fluctuations, the yearly upward trend has continued. We're now at 390 ppmv, rising about 2.2 ppmv per year.
Maxwells
***
"How much warmer seems good for you? 1 degree, 3 degrees? 10?
I.e., we have indirect evidence that ~40 million years ago, atmospheric CO2 levels were comparable to now, along with elevated temperatures.
http://www.sciencemag.org/content ... .abstract
But for CO2 levels comparable to what's projected for later this century (500 - 650ppmv), global average temperatures eventually rose by as much 29 degs F higher.
Think you'll like another 29 degrees F hotter? How about your great great grand kids? Think they'll agree with you?
Well, OK. Maybe you don't care about your distant progeny. Fair enough. But some of us do.
http://www2.ucar.edu/news/3628/ea ... e-climate”
***
Even with overwhelming evidence, scientific theories can't proven; only disproven. But good theories stand the test of time; bad theories are inconsistent with evidence. E.g., volcanoes emit less than 1% the CO2 that fossil fuel burning does. Earth orbital changes take many thousands of years. Our global warming is happening w/i 200 years. Sunshine is in a lull. So, forget those explanations.
However, multiple methods show
1) CO2 is a greenhouse gas, which has increased 40% since 1850 when humans started burning fossil fuels BIG.
2) Human CO2 production has exceeded (currently double) its global rise rate since 1850. This says that human causes are large enough to impact CO2 levels and that Earth incompletely absorbs excess CO2 production.
3) As a greenhouse gas, temperature rises provoked by excess CO2 also increases water vapor, which is also a greenhouse gas. Measurements show this is happening.
4) So, rising CO2 induces rising temperature due to both itself and increased water vapor.
5) Dead plant/animal material stops absorbing new carbon. So the radioactive carbon in it decays, changing its carbon isotope ratio. When changed carbon gets dug up and burned after millions of years, it changes atmospheric CO2. isotope ratio. Those changes are consistent with excess CO2 from burning fossil fuels. That fingerprint's the clincher.
6) All other accounts fail the evidence.
***
Antarctic ice core data verifies the 40% increased CO2 figure. CO2 is well-mixed world wide. So, Antarctic sampling is representative of the rest of the globe and it's very clean - no contamination. Atmospheric gases get embedded as microscopic air bubbles w/i snow, which gets compressed to ice by later snowfall. It snows more in winter. So, you see yearly rings, like tree rings. So, these ice core samples from Epica and Vostok trace very slight yearly changes in atmospheric gas composition, as far back as 780,000 years.
'
Quite a feat, eh? Not for wimps.
However, since ~1957, there's direct CO2 measurements from Mauna Loa Observatory, starting with Charles Keeling's first 10 year data set, which I viewed in 1968. I think that first set was around 320 - 330 parts per million by volume (ppmv).
It also showed the expected seasonal CO2 dip in the northern hemisphere's summer, but with an even stronger climb during northern hemisphere winter. This happens because most of the Earth's land masses and thus vegetation is in the northern hemisphere. (Oceanic plankton counts for less.) And photosynthesis (which removes CO2) is stronger in summer when plants have leaves. Plants mostly respire (give off CO2) in winter. Animals of course always respire, as they don't photosynthesize.
Despite seasonal sawtooth fluctuations, the yearly upward trend has continued. We're now at 390 ppmv, rising about 2.2 ppmv per year.
Maxwells