What is important is the relative concentration of CO2 compared to the other greenhouse components – and of course those components that introduce negative forcing, such as sulphates. If the current CO2 concentration accounts for 26% of the greenhouse effect, then it is fairly obvious that doubling CO2 is going to have an impact. Current estimates are about 3°C per doubling of CO2.

I to have grappled with the issue of how a small amount of CO2 can have such an effect. I have read the literature but did not have that eureka moment until I read this from Jihong Cole-Dai at the Rabbet Run. I hope it helps you to:

“Many chemists are skeptical about the science of global warming because it doesn’t fit well with the frame of their chemistry mind-set. An example is the letter by Thomas E. D’Ambra in which he asks, “How many kilocalories of infrared energy can a ton of carbon dioxide absorb?” (C&EN, July 27, page 6). The question implies that the amount of carbon dioxide in the atmosphere may be insufficient to cause a change in the trapping (the greenhouse effect) of the outgoing energy by Earth’s thermoradiation.

I encountered questions from professional chemists similar to this while giving presentations on global warming, and I was initially unable to come up with a satisfying answer. The basis of the question is legitimate: CO2 absorption in the infrared region of the spectrum is weak on a per-molecule basis, and CO2 is a minor component of the atmosphere, with a current concentration of 380 ppm (only 380 molecules out of 1 million molecules in air are CO2).

Any person, particularly a skeptical chemist, would expect that, with the nonstop emission of thermoradiation from Earth’s surface, all CO2 molecules would soon be in the excited vibrational and rotational levels of their molecular energy states, and none would be left to absorb more outgoing energy. Hence, the greenhouse effect would be very limited.

However, CO2 molecules do not exist alone in the atmosphere. The excited molecules can and do transfer their excess energy to other molecules and return to ground states and are therefore ready to absorb thermoradiation again. The transfer of the initially absorbed energy to other nonabsorbing molecules, called “quenching” in photochemistry, enables a relatively small amount of greenhouse gases such as CO2 to continuously absorb the thermoradiative energy, which otherwise would escape into space, and to convert the radiation back to thermal energy that stays on Earth.

Therefore, the answer to D’Ambra’s question is that an unlimited amount of infrared radiative energy can be absorbed and returned back to Earth by small quantities of atmospheric CO2 and other greenhouse gases. The greenhouse effect is continuous along with Earth’s thermoradiation.”

And yet recent records show the oceanic global temp is the warmest ever recorded. This from NOAA:

“The seasonal (June-August 2009) worldwide ocean surface temperature was also the warmest on record, 0.58°C (1.04°F) above the 20th century average of 16.4°C (61.5°F).
In the Southern Hemisphere, both the August 2009 average temperature for land areas, and the Hemisphere as a whole (land and ocean surface combined), represented the warmest August on record.”

“sea level static” – Dick Treadgold

Wrong again. Don’t you get tired of being wrong?

http://www.cmar.csiro.au/sealevel/sl_hist_last_15.html

“Shall we mention polar ice” – Dick Treadgold

Yes, we shall. That’s fast disappearing. 2009 3rd lowest Arctic sea ice extent minima:

http://nsidc.org/images/arcticseaicenews/20090917_Figure2.png

2008 lowest ever Arctic sea ice volume since records began.

http://nsidc.org/news/press/20081002_seaice_pressrelease.html

Antarctic ice mass loss:

http://grace.jpl.nasa.gov/news/index.cfm?FuseAction=ShowNews&NewsID=18

http://www.sciencemag.org/cgi/content/abstract/311/5768/1754

http://news.bbc.co.uk/2/hi/science/nature/8200680.stm

Tough being a denier, when the whole physical world disagrees with your faith.

Reading these comments, I was waiting for the dressed up version of old denier canards to surface.

“Co2, is such a tiny amount in the atmosphere!.”

“That small quantity of cyanide can’t hurt anyone. It’s only a trace amount!”

Well Dick, I’m waiting too. Please enlighten the world of the evidence which explains the recent warming, other than CO2e.

Who, exactly, is trying to destroy the economy?

Oram’s whole point is that, whether or not you believe in AGW, the rest of the world now does, and is doing something about it. Therefore, the biggest threat to our economy would be to do nothing about AGW.

Implementing an ETS that does not actually reduce emissions certainly has the potential to destroy our economy, once the rest of the world realises that we have done nothing and we get a big bill for our share of the emissions.

So right now I would say that it is you, and Roger and the rest of the denialists who are trying to destroy our economy.

All the scientific work I have seen make it plain that anthropogenic release of CO2 is the primary driver of the recent warming. That is why we need an ETS.

Now, if you have some scientific evidence that contradicts this, please present it, otherwise you do not have a case.

If you are genuine, you will present a scientific case. It is pointless having a conversation if you are not going to back it up with science. References, please.

You’re arguing yourself into a corner now. Oram didn’t explain the why in the next sentence at all. Talk about missing the point. As he says, it’s because of the international commitments that we need the trading schemes. He builds the argument and finishes that with:

A good ETS sets a price signal and generates revenues that government and business can invest in the changes we must make.

There’s your why!

But I have a hunch you were looking for re-iterating of what are now foregone conclusions – that Anthropomorphic Global Warming is real. You saw the word “why” and then were looking for something to attack. The Zombie march isn’t until 31st Oct you know.

Yes, I remember the issue; in mentioning “ad hominem” I had not forgotten it but was answering Gareth, who had digressed to instructing me in the Latin. But personally insulting remarks are clearly “against the man” and independent of the issue.

When I first responded to you, I was answering three points you gave without references. Why should I give references? I’m pleased to discuss the issues. If you’re genuine, by all means post something on my blog.

But I’m still waiting (remember?) for an answer to my original question to Oram about the reasons we need an ETS.

I still want him to give us what he promised. These are his words: “To understand how the government is destroying the Emissions Trading Scheme, it’s important to remind ourselves why we need an ETS in the first place.”

If his next sentence is truly his only reason, then he is naive and he knows nothing about global warming.