Long-term climate forecasts not reliable
Abundant summer rain in SA has taken the weather forecasters and climatologists by surprise. They did not expect La Niña to persist for a third successive year.
La Niña (Spanish for little girl) describes an upwelling of cooler water in the Pacific Ocean that brings more precipitation in Southern Africa, and less to parts of South America. Its opposite is the little boy — El Niño — associated with warmer seas and a drier SA.
The quality of weather forecasts has been improving apparently, but predictions more than 10 days ahead can still surely not be described as confidently made with little margin for error. What confidence should we attach to climate forecasts 50 or more years into the future? Yet society is being called upon, vociferously, to believe in the accuracy of such climate models and their predictions of harmful global warming.
We are being called upon — forcefully instructed may be a more accurate description — to eliminate emissions of carbon dioxide (CO2), at enormous expense, to limit global warming. Costs of the astronomical order of $200trillion are bandied about. Given that hundreds of millions of the citizens of the world’s poorest economies still lack clean and affordable energy to heat their shelters and cook their food, it is extremely unlikely that resources of that magnitude will be willingly supplied.
For them to do so, climate models will not only have to be able to accurately estimate the volume of CO2 and other gas emissions to come and predict within narrow limits their effect on average temperatures, but also how different parts of the planet will respond. And they will have to estimate the influence of other natural forces that act simultaneously and powerfully on climate.
For example, there is significant disagreement among experts on whether we are about to enter a relatively quiet sunspot cycle, which normally leads to a period of cooling. Another persistently powerful force on climate is ocean flux, of which La Niña and El Niño are examples. The consensus view among experts is that the Atlantic Multidecadal Oscillation, a cyclic phenomenon of sea surface temperature anomalies in the north Atlantic Ocean that switches between positive and negative temperature phases over about 80-year periods, is about to shift to a cool phase.
Climate models are necessarily highly complex and hence prone to error. Climatologists therefore carry grave responsibility for the accuracy of their models. They and politicians will be held responsible for the expected trade-offs of present costs (higher taxes and energy prices) for future — always less than certain — benefits.
I am no climate expert, but I am well aware of the fallibility of long-term forecasts of the state of any economy. And of the weakness of scenario building, which invariably attaches too much weight to recently observed phenomena. I am conscious that the planning horizon of any firm that commits to capital expenditure is seldom beyond 20 years, for very good reasons. Relying on benefits beyond 20 years is too uncertain to influence current outcomes, and this is also true of governments and their plans.
It makes good sense to wait and see what dangers and opportunities climate change may bring over the long run. A stronger, better-endowed economy will have the capacity to better manage adversity. The potential danger of global warming adds to the case for faster not slower growth; for more rather than less resilience. Humans are well practised in adapting to challenges and can be relied on to cope with continuous climate change.
Relying on ambitious plans imposed top-down has not yet proved a useful strategy for humanity. The plan to control climate through intervening severely in the global market for energy is highly ambitious, and top-down in a manner not ever embraced before.
Meanwhile, the search for cheaper, less noxious, less dangerous and more reliable energy sources is one of the positive steps for mankind that is still worth taking.