Professor Tim Flannery caused a stir last week when he told Macquarie Radio’s Andrew Bolt that cutting emissions will not reduce world temperatures for 1000 years [partial transcript here]:
If the world as a whole cut all emissions tomorrow the average temperature of the planet is not going to drop in several hundred years, perhaps as much as a thousand years because the system is overburdened with CO2 that has to be absorbed and that only happens slowly.
Here’s a summary of what Professor Flannery meant by this remark. Later in the post I’ll talk about where these predictions come from.
- Yes, temperatures probably will not drop for 1000 years;
- However, due to human carbon emissions, if we do nothing, temperatures will rise by a best estimate for 4.0 degrees celsius;
- Therefore, if no action is taken, we will be stuck with 4.0 degree celsius higher temperatures for hundreds of years.
Later in the interview, Professor Flannery tries to give some context to his remarks:
Bolt: That doesn’t seem a good deal. If we spend trillions of dollars to cut world’s emissions that we won’t notice the difference, well our great-great-great-great-great-grandchildren won’t even notice the difference.
Flannery: It will just keep getting worse if we don’t. That’s the problem.
Background: Andrew Bolt is a conservative columnist who is opposed to the mainstream consensus on climate change, and Professor Tim Flannery is the Chief Climate Commissioner selected by the current Labor government.
What does the science say about the effect of reducing emissions? According to the IPCC Fourth Assessment Report, the choice is between a 1.8 degrees celsius temperature rise – achieved by cutting carbon emissions – and a 4 degrees celsius temperature rise.
A study by NOAA (National Oceanic and Atmospheric Administration) predicts that climate change caused by human created carbon dioxide is largely irreversible for 1000 years. This is presumably what Professor Flannery was talking about.