The American Geophysical Union (AGU) has released a statement on climate change in which they state
Humanity is the major influence on the global climate change observed over the past 50 years. Rapid societal responses can significantly lessen negative outcomes.
Our influence on the climate is minor but beneficial.
Wow, that’s very certain. No caveats or uncertainties. Not very scientific in my opinion.
Anyway, I won’t go through it all, but thought I would address a few of Monckton’s claims. He says
The mean residence time of a CO2 molecule in the atmosphere is 7 years, so the AGU must recognize that its earlier fears that anthropogenic emissions will influence the climate system for millennia have proven unfounded.
Hold on, what Monckton is referring to here is the residence time of a single carbon dioxide molecule. There is a carbon cycle in which carbon dioxide moves through the atmosphere, into the biosphere (plants) and into the oceans. A typical carbon dioxide molecule will remain in the atmosphere for a few years before being absorbed by a plant or the oceans. However, it’s typically replaced by another carbon dioxide molecule released from the oceans or from the biosphere. Therefore, 7 years is not the timescale over which the enhanced atmospheric CO2 concentrations will reduce. That is hundreds of years, consistent with the AGU statement. You can read more here. Monckton goes on to say
Yet the models have consistently over-predicted global atmospheric and oceanic warming. According to satellite measurements, for 16 years 8 months, or 200 months, there has been no global warming at all.
Nonsense. Global climate models have over-predicted surface warming but they’re still consistent at the 5 – 10% level. This means that the models suggested that there was a 5 – 10% chance that we’d observe what we do. That’s not failing. Furthermore, ocean heat content has continued to rise in line with (or possibly faster than) expectations. This means global warming hasn’t stopped. It just means that, at the moment, a smaller fraction of the excess energy is heating the surface than expected. This might be surprising, but does not mean its stopped. It definitely hasn’t (or, to be precise, there is very strong evidence that it hasn’t). Monckton then adds
it is known that much of the loss of Arctic sea ice is attributable to natural influences, and half of that loss since 1979 has been compensated by increases in Antarctic sea ice.
The first part of this statement is completely at odds with current scientific evidence. Arctic sea ice is reducing faster than even the models predict. The latter part of the statement is largely irrelevant. As I try to explain in this post, from a global warming perspective, Antarctic sea ice is not really relevant. It may have significance with respect to climate change (i.e., that it is happening) but isn’t really an indicator of global warming and certainly doesn’t compensate for the loss of Arctic sea ice.
So, Monckton also discusses how everything we’re observing now is consistent with the range of possible natural variations (no, there’s not really any evidence to support this) and makes some very definite statements about how we’ll benefit if warming does continue (no, there’s no evidence that this is true either). Anyway, I should probably stop rebutting what Monckton says as he keeps regurgitating all the same arguments that many have already shown to be wrong (or, at least, have no evidence to support). That’s really all I was going to say. The AGU statement seems very measured and sensible. Monckton’s just seem wrong.