(Use headphones if you listen to the tape at work.)

http://www.bluevirgi...-on-blue-virginia

Good for him. I hope it gets more attention, for more than the profanity.

Cheers,
Scott.

1) Yes.
2) Maybe.
3) No. http://climate.nasa.gov/causes/

But several lines of evidence show that current global warming cannot be explained by changes in energy from the sun:

* Since 1750, the average amount of energy coming from the Sun either remained constant or increased slightly.

*If the warming were caused by a more active sun, then scientists would expect to see warmer temperatures in all layers of the atmosphere. Instead, they have observed a cooling in the upper atmosphere, and a warming at the surface and in the lower parts of the atmosphere. That's because greenhouse gasses are trapping heat in the lower atmosphere.

* Climate models that include solar irradiance changes can’t reproduce the observed temperature trend over the past century or more without including a rise in greenhouse gases.

4) No. http://news.discover...imate-110627.html

"The question of whether or not volcanoes emit more CO2 than human activity is one I get more than any question in my email from the general public.' said Terrence Gerlach, a retired volcanologist, formerly with the Cascades Volcano Observatory, part of the US Geological Survey in Vancouver, Wash. Even earth scientists who work in other areas often pose him the question, he said.

To lay out a clear answer, Gerlach compiled the available estimates of CO2 emissions from all global volcanic activity on land and undersea and compared them with estimates for human emissions. He published the compilation in Eos, a publication of the American Geophysical Union.

Researchers estimate the amounts of carbon dioxide released by terrestrial volcanic eruptions by methods including remote sensing or flying through clouds of erupting volcanic gas, and by measuring certain isotope concentrations near undersea volcanoes. Carbon dioxide is dissolved in magma at great depths and is released as the magma rises to the surface.

"A lot of climate skeptics claim that volcanoes emit more CO2 than humans do," Gerlach said. "They never give any numbers, but the fact is you will never be able to find the volcanic gas scientist that will agree to that," he said.

[...]

While there is uncertainty in the measurements--researchers estimate between 0.13 and 0.44 billion metric tons per year, with their best estimates between 0.15 and 0.26 billion tons--even the highest end of the range is dwarfed by anthropogenic emissions of 35 billion metric tons in 2010.

Gerlach noted that human land-use changes alone, which include deforestation, release 3.5 billion metric tons per year. Cars and light-duty trucks produce 2 billion metric tons; even cement production produces 1.5 billion tons. Any of these by itself is still several times higher than the annual emissions of all of the world's volcanoes .

Pakistan or Kazakhstan each produce about the amount of CO2 as volcanoes do each year, Gerlach noted in the article.

5) Yes, there were many times in the past when the Earth was warmer and there were no humans around. That's why we should be even more concerned now. The Carbon Cycle was in a sort-of balance without billions or trillions of tons of ancient carbon being thrown up in the air in the course of a few hundred years. And yet there were times when the climate changed rather quickly. Ocean levels changed by tens of feet. Glaciers advanced and retreated. Etc.

There is no doubt that CO2 is a greenhouse gas. Look at Venus. If more CO2 is added to the atmosphere more quickly than the system can handle, the temperature of the Earth will increase. And it will lead to more CO2 release in the Arctic (permafrost melting, fires) and more sunlight being absorbed (less ice to reflect it).

We know a lot about the sources of CO2 by looking at the isotopes. CO2 that has been locked up in coal and oil for millions of years has different ratios of C12, C13 and C14 than does CO2 from burning plants (due to different radioactive decay over time). http://www.realclima...tivities-updated/

It's good to be skeptical. But the critics are wrong in this case.

HTH.

Cheers,
Scott.

Why would its output have changed significantly over a mere 150 years?

Yes, it puts out big numbers, and it varies a bit over time. But that doesn't explain the CO2.

HTH.

Cheers,
Scott.
(Who agrees that burning stuff won't be an issue in a few hundred years, but most of us and our kin will be dust long before then...)