The pessimistic perspective is that these measures carry additional risks as we've already severely damaged the environment accidentally because we didn't understand it well enough, and any more messing about is liable to make things far worse and far sooner.

If that becomes the case, we may have little choice but to attempt more extraordinary measures (i.e.

use of radio isotopes in carbon dating-41

In the event that such things are a dead end (and there is the opinion that it's too late to reverse climate change by merely reducing or stopping what we're doing) there is geo-engineering. This involves trying to force climate change back in the opposite direction intentionally, or with what has been described as terraforming Earth.

Among these options is lacing the atmosphere with particulate matter in order to seed clouds, artificial carbon sequestration technology to actively remove the carbon dioxide from the atmosphere at a rate faster than natural sinks such as photosynthesis and ocean carbonates, and constructing sun screens in orbit.

For example, the common talking points about it being warmer during the Medieval Warm Period and low climate sensitivity (i.e.

"climate is much more stable than that") contradict each other, because the existence of a Medieval Warm Period necessitates high climate sensitivity.

Also note that while water vapour is correctly listed as a GHG, the human emissions of water vapor are not important in forcing climate change; water vapour is best thought of as a response to temperature change rather than a cause, because its atmospheric lifetime is very short (about 10 days), unlike other gases such as CO have ranged from 2°C to 6°C, there's broad agreement that anything above 2°C will mean we are beyond recovery.

The International Energy Agency suggests that the window to prevent this from occurring will close by 2020, emissions have been stabilizing but methane emissions have risen dramatically during the past ten years for unknown reasons.

However, it requires energy to operate and a 2011 study estimated that processing the whole atmosphere would not be cost-effective.

One of the authors noted that planting vegetation is more feasible but would require a significant amount of land.

and there is simply not enough storage on earth for all the wood forests of the needed magnitude would produce.

However, we could bury the resulting biomass underground, in effect recreating the origin of the fossil fuels that got us into this mess in the first place.

So climate denial inevitably involves a barrage of bad-faith misdirection tactics that do nothing to rebut the scientific consensus at issue.