Is further warming of 2°C to 3°C unstoppable?

No, I don't think so. Recent studies have shown that we can limit the warming to 2°C by 2100 by reducing global GHG emissions 50-80% by 2050.

http://www.realclimate.org/index.php/archives/2009...

Your point about long-term climate sensitivity is a valid one, but we also have the opportunity to eventually reduce the atmospheric CO2 concentration after we stabilize it. This is why many individuals like James Hansen are proponents of eventually reducing the atmospheric CO2 level to 350 ppm.

http://www.columbia.edu/~jeh1/2008/TargetCO2_20080...

I think it's plausible that we'll have the technological means in the future to sequester sufficient carbon to reach this goal before warming in excess of 2°C occurs, assuming we successfully reduce global CO2 emissions in the meantime.

*edit* Yeah Keith, jim z is right. Stop pretending you know stuff just because you understand basic physics!! Don't you know that "radiation budget" and "radiative forcing" are just terms made up by alarmists to scare people into believing AGW?

stable question; if it weren't for worldwide warming 25,000 years in the past human civilization would not have progressed a lot. the consumer-friendly factor in all of that's the solar. It for sure impacts the earth to the comparable degree through fact the different planets interior the photograph voltaic gadget. Mars has had the comparable temperature transformations through fact the Earth throughout the comparable term. i assume Al Gore believes that our marketplace is likewise warming the exterior of Mars. and how many vehicles have been on the roads 25,000 years in the past on the top of the final ice age?

Unfortunately a warming of another 2-3C is probably in store for us regardless of what we do.

People and governments are not likely to reduce their use of fossil fuels over the long term because it will be seen as too damaging to their economies. Any sort of large scale wars would also nullify carbon reduction. Arms races of any kind require significant amounts of energy, any advantage a nation can get over another will be used.

Further increases in global warming could eventually be catastrophic, but I don't expect to see it in my life time. We have a lot of pressures on the system, eventually one of them will get us.

The dinosaurs went extinct, what makes us think we are so special? We may not go extinct, but I think we will see a significant decline in human population.

Probably. The extra CO2 from anthropogenic sources will take 10's, if not 100's of thousands of years to naturally wash out of the atmosphere.

You state:

Further, we know that the equilibrium temperature has not yet been reached because of the current imbalance in Earth's radiation budget:

You know nothing of the sort. Stop pretending to know things you don't. One of the most important steps is science is acknowledging the limits of your knowledge. There is nothing in the recent warming that is out of the ordinary from past trends. There is no reason to assume the CO2 is suddenly the climate driver. When people pretend to know things they don't, they tend to make unsubstantiated claims which you have clearly demonstated.

Wrong little robber girl. You are like a todler that thinks they understand things they don't.

i think we have already overshot safe levels. our descendents will have to do a lot of work to stabilise the climate; how much will be determined by how soon emission of greenhouse gasses peak.

we as a species are like a toddler locked in a car on a hill, who has accidentally knocked off the handbrake. we have a very short time to learn how to drive....

You have to remember that our data for the preindustrial temperatures are at the end of a mini ice age where the temperatures where below average. We still have a few degrees to match the temperatures of the Medieval Warming period. Then again, most climate scientists only look at the negative and ignore any positives.

It depends on how good we get at sequestering (if that can be made to work), alternatives including nuclear, renewables ...

But even if we can't stop 2o now, we sure want to stop 4o and we MUST stop 6o, which is where we can go if we carry on as usual.

If we carry on without any warming for another decade - you might have to rethink your beliefs. As much as it is unthinkable to you now, you may become a climate change skeptic. Lets wait and see if warming really is still happening before we start using it as a justification for loads of new taxes.

Hopefully!