[m_mueller]

So, you're sitting in a car driving 100mph towards a wall. The car's safety system warns you, saying 'collision ahead, break NOW'. You're thinking "hey, no problem, no car since 1880 has driven into this wall, it must be a hallucination - I'm keeping my foot down baby".

Analogies used here:

The car - Energy policies

The safety system - Climate models

The warning - Result of these models

You driving into a wall - Laymen's opinions about why these models don't apply.

To put it differently:

1) There's a time delay of several decades between putting out the CO2 and temperature rise. What we're feeling now is the effects of energy policies in the 60ies and 70ies.

2) Since the 70ies our CO2 output has risen considerably, mainly due to emerging markets.

3) Most of this 0.8 degree warming you're talking about has occurred in the last 30 years.

Well - would you bet on the wall being an illusion, or would you rather brake just in case?

[smky80]

If my car's system had the same track record and fundamental flaws as the climate models commonly cited, I would be inclined to ignore it. By track record I mean predicting a 3 degree C increase per doubling of CO2 and experience showing only half of that. The fundamental flaw is the assumption that positive feedback effects will triple the 1 degree C per doubling CO2 greenhouse effect, when these feedback effects (clouds and water vapour) are so difficult to model correctly.

Pretty sure the time lag of decades for temperature increase is simply false. Most of these models were predicting temperature increases since 1998 which haven't happened.

Finally, I probably would consider not braking at all if I couldn't possibly come close to stopping in time to prevent a fatal impact. If you really think a 3-6 degree C temperature increase is coming, the only thing that is going to do anything is something like a 50% drop in fossil fuel consumption. The world can't even agree on a 10% cut that won't do anything. EDIT: That's why I think these are really anti-peak oil policies, because a 10% cut actually helps there.

[m_mueller]

I see where you're coming from. When it comes to climate models, lots of feedback loop, both positive and negative ones, are being thrown around - you can basically adjust models arbitrarily to your political liking. Adjusting these models to real data is a never-ending process as long as we don't have the computational power to both resolve much denser grids and timesteps and include more parts of the equation than we do now. However, when it comes to balancing these things out to give an accurate prediction, I tend to trust organizations like NASA, IPCC and NOAA over the typical right wing think tanks that you see throwing together these denialist reports. Yes, we do know about negative feedback loops, the scientific consensus is just that they're much weaker than what we're doing to the atmosphere. Also, the 1998 measurement that gets thrown around is very misleading - have a look at [1].

Noone is claiming these models are perfect and the temperature increase estimates may be off by some margin - all I'm saying is that as long as we're sure current CO2 levels aren't going to kill our future, we better stop increasing them, given scientific consensus. When the doomsday scenarios come from scientific studies and stop including low probabilities, it's better to take them seriously rather than bet our home planet on them being all wrong.

[1]http://www.nasa.gov/topics/earth/features/upsDownsGlobalWarm...

[smky80]

I don't trust the IPCC because the actual results haven't matched their models, regardless of what the "scientific consensus" is on negative feedback loops.

And again, stopping the increase of CO2 would require massive global emissions cuts, which would require a new energy infrastructure.