In the make-believe world of Climate Debate Daily, where there are two sides to a great “debate” on the reality of climate change (there aren’t), a great gulf is opening between the opposing teams. Cranks are investing a great deal of (wasted) time and effort into spreading the idea that the world is cooling, while climate scientists think a new record high global temperature can’t be far away.
Thus, using several fundamentally different mathematical techniques and many different data sets, seven scientists all forecast that climatic cooling will occur during the first decades of the 21st century. Temperature records confirm that cooling is under way, the length and intensity of which remains unknown. [â€¦] Perhaps a reassessment will finally occur when two-metre thick ice develops again on Father Thames at London Bridge, or when cooling causes massive crop failure in the world’s granary belts.
Deniers should show caution, Hansen insisted: most of the planet was exceptionally warm last year. Only a strong La NiÃ±a – a vast cooling of the Pacific that occurs every few years – brought down the average temperature. La NiÃ±a would not persist, he said. “Before the end of Obama’s first term, we will be seeing new record temperatures. I can promise the president that.”
There’s a collision comingâ€¦
Hansen’s reference to Obama’s first term is actually slightly less forthright than the the GISS summary for 2008. After considering the impact of the low total solar irradiance associated with the trough of the current solar cycle, it concludes:
The Southern Oscillation and increasing GHGs continue to be, respectively, the dominant factors affecting interannual and decadal temperature change. Solar irradiance has a non-negligible effect on global temperature [â€¦]. Given our expectation of the next El NiÃ±o beginning in 2009 or 2010, it still seems likely that a new global temperature record will be set within the next 1-2 years, despite the moderate negative effect of the reduced solar irradiance.
Carter’s article pins its hopes on a bunch of the climate equivalent of stock market chartists — people who look back through climate history and try to find patterns they can push out into the future. This sort of approach is doomed, as Deltoid points out, because in order to make this sort of prediction you have to assume that all the things that made temperatures change in the past are still operating today, and that means you have to ignore the effects of increasing amounts of greenhouse gases.
There’s really no debate here. The atmospheric physics is clear enough. Greenhouse gas forcing is increasing every year, and will rapidly overwhelm the effect on the planetary heat budget of any short term reduction in the solar energy arriving at the planet. But clearly there are people who are prepared to invest a great deal of personal and professional mana in the mistaken idea that cooling is either here or coming. What will happen when the next El NiÃ±o brings a new global temperature record? (My money’s on 2010 or 2011, if anyone’s interested.)
It would be nice to think that Carter, Easterbrook and the rest would acknowledge that “cooling has stopped”, just as they are so keen to make people think that “warming has stopped”, but I find it hard to believe they will. In order to maintain their status as climate cranks and denialists, they already have to ignore so much evidence that one more inconvenient fact will hardly make any difference. But the cognitive dissonance may become deafening.