There were some recent senate votes on the Keystone XL pipeline that were very revealing about the state of climate denialism.

The first amendment, offered by Sheldon Whitehouse (D-RI), was apparently supposed to embarrass Republicans into declaring that climate change is a hoax, on the record.  It suggested that there be a “sense of the senate” resolution on whether climate change is real, or a hoax.

Senator James Inhofe, who believes that there is a global conspiracy among scientists to promote the “hoax” that mankind’s fossil fuel emissions are altering the climate.

To some people’s surprise, it passed 98-1, with notorious climate change denier senator James Inhofe even offering to co-sponsor it.

Inhofe then explained his reasoning:

Climate is changing, and climate has always changed…The hoax is that there are some people that are so arrogant to think that they are so powerful that they can change climate. Man can’t change climate.

No word on whether Inhofe thinks women can change the Earth’s climate.

Anyway, to put a fine point on it, senator Brian Schatz (D-HI) then put a second amendment, declaring that climate change is real AND that human activity is a significant contributor to it.  That amendment “failed” 50-49 (it required 60 votes to properly pass under senate rules).

This is, I think, a very important pair of votes for those who want to “move the needle” of public opinion regarding action on climate change.  It reveals the current state of denialism: the Earth is getting warmer, but humans are not the cause.  This important because:

1. It means that news reports about how the Earth is warming aren’t going to do anything beyond keeping the issue alive and keeping the urgency among those who understand the science high.  The “official party line” (literally!) of the denial camp concedes that the Earth is warming.
2. It means that promoting news about how hot the Earth’s surface is getting will not persuade denialists — in fact it will probably harden their positions, because it will convince them that the promoters do not understand why there is a hoax.  Pounding the table on a point that has already been conceded is evidence that you don’t understand the debate, so it discredits your authority, which strengthens the opposition’s certainty in their position.  There is also the backlash effect at work.
3. It means that further education needs to be about the “how we know we’re doing it” and the causation.  Since denialists agree that the Earth is warming and that we’re pumping out fossil fuels, showing them correlation will only strengthen their views because of item 2 above.  Instead, we need to show them that the CO₂ in the atmosphere is significantly increasing and that the increase is because of fossil fuel burning.

This figure shows a 25% increase in CO₂ concentrations. This is not small. I like to point out that if you gained 25% more weight, you’d be something like 40 lbs heavier — that’s not a little, that’s a whole lot.

The next argument to emphasize is that we know it’s from fossil fuels.  This can be shown from pure numbers: the atmospheric increase is 15 billion tons per year, and humans are emitting 30 billion tons per year.  The Earth is thus burying half of our fossil carbon emissions!  But it’s not enough.

There’s also a misconception that volcanos are more important.  Actually, natural emission is about 0.1 billion tons per year, which is negligible.

Keep these points in mind when arguing with skeptics.