Video description

On the 19th of July in 2011 the National Press Club of Australia held a debate on climate change. I will be analysing the claims Monckton made during the debate and if they are correct or not.

In this particular section of the debate Monckton makes the claim that based on current trends the increase in global temperatures cannot accelerate.

Transcript

These are the people who need your help, not merely critically to - uncritically to accept consensus but instead to ask the question about the fraudulent science which is in each of the conclusions of the three major IPCC reports; ask questions about why it is that global warming is happening at the moment and has been happening over the last 60 years at only one-fifth of the rate now predicted by your government; ask the question how in science there could be any chance that the rate of just roughly one Celsius per century of warming that has been occurring can suddenly become roughly five Celsius per century as it were overnight. There is no physical basis in science for any such sudden lurch in what has proven to be an immensely stable climate.

Here Monckton summarises points he made during his opening statements for the debate. I'll ignore those for the moment, but he does expand on his claim that the world will only warm by 1 degree during this century.

He's basing this on the claim that we've seen an increase of 0.1 degrees per decade, and if we then extrapolate this into the future this means we can expect a warming of about 1 degree.

The problem with this is that it's completely wrong. Not in the sense that the figures he used are wrong, as they are very close to the actual figures, but in how he calculated the number is wrong. I've repeatedly mentioned that for a doubling of CO2 we can expect an increase in temperature of about 3 degrees. This is what scientists call the equilibrium climate sensitivity.

What scientists mean with this is that if you increase CO2 this will introduce an energy imbalance, more energy is now absorbed by the planet than emitted. This is caused by the planet holding on to heat energy longer due to CO2, and this difference is what makes the planet warmer. After a while the outgoing energy will again match the incoming energy, but the increase in temperature remains. And this increase is what scientists are talking about when they say that a doubling of CO2 will cause a warming of about 3 degrees.

What Monckton did was project a trend. This doesn't tell you anything about the temperature the planet will eventually achieve.

Also one big problem with how Monckton calculated this is that it doesn't take into account thermal inertia. It just takes time for a planet to warm. For example our oceans have been absorbing the vast amount of the extra heat our planet is now holding on to. These oceans need to warm first before global temperatures can increase.

His calculation also does not take into account that CO2 emissions have been increasing. This alone will mean that there will be more warming than Monckton predicts based on his figures.

The climate system is far too complex to predict future global temperatures based on a trend projection.

Sources

1. The equilibrium sensitivity of the Earth’s temperature to radiation changes
2. An exponential increase in CO2 will result in a linear increase in temperature
3. Climate sensitivity
4. An exponential increase in CO2 will result in a linear increase in temperature

Media resources

1. Climate Sensitivity
2. NASA - Striking a Solar Balance
3. NASA | Supercomputing the Climate
4. CO2 Emissions vs IPCC Scenarios
5. NASA | NASA's Analysis of 2012 Global Temperature