Driving through the drought-stricken Central Valley of California last month was a sobering experience: Vast swaths of once productive crop land turned to desert; thousands of almond trees and fruit trees left unwatered, gray and dead, their limbs stripped of leaves and bark. In some areas, it was almost post-apocalyptic.
You also saw a lot of signs like this:
Farmers in the Central Valley have always depended on an extensive, expensive system of taxpayer-financed irrigation. Without it, their land would be almost useless for agriculture. And with the region facing the worst drought in recorded history, and probably the worst in at least several hundred years, they want every drop possible to be diverted to their property, regardless of competing demands on a very scarce resource.
I can understand the farmers’ desperation. In their drive for water, they’re also drilling wells that are a thousand feet deep or more, but as they drill deeper and pump more water, the deep aquifer is retreating. And as groundwater is pumped out, the land above it is subsiding at a rate of a foot a year in some places. What they’re doing is probably just not sustainable on the scale at which they’re doing it, and there’s nothing Congress can do to change that reality.
This year alone, the drought is estimated to have cost the California economy some $2 billion and 17,000 jobs, while driving up the price of food for just about everyone in the entire country. And so far there’s no sign of it easing.
What’s causing it? According to a new study funded by the National Science Foundation, the drought is very likely the consequence of manmade global climate change. The study found that a drought of such intensity is now three times more likely than it would have been in the absence of greenhouse gas emissions. However, it’s also important to note that experts at NOAA consider the question still open, citing two other studies of the drought that have failed to find a linkage to climate change.
That’s the nature of science. It doesn’t reach unanimity, or even consensus, without going through a lot of give and take. Egos get bruised, friendships get broken, but what matters in the end is that they get it right. It also helps to explain why the notion of a science-wide conspiracy or hoax surrounding climate change is so downright ludicrous.
In Australia, however, something different is going on. Five different research teams, operating independently and using distinct research methods, have reached the same identical conclusion: Australia’s record heat wave of 2013, which produced temperatures as high as 114 degrees in Sydney and brush fires and dust storms throughout the continent, “was virtually impossible without climate change.”
“Five teams of researchers …. concluded that the record temperatures for the whole of that year would almost certainly not have occurred without man-made climate change, and that the chance of heatwaves occurring was more than 2,000 times greater because of human-caused climate change….
One set of models factored in natural variations in climate and human influences on climate, while another set showed what temperatures would have looked like without man-made climate change.
Out of 12,500 simulated years, only one result in the latter group produced temperatures higher than those seen in Australia in 2005 – the hottest year before 2013 – and none as hot as 2013.”
In assessing such studies, it’s important to note that even the Australian researchers use terms such as “almost certainly” and “virtually impossible” rather than outright impossible. That’s because In a complex system such as climate, it is outright impossible — rather than virtually impossible — to state the cause of anything with 100 percent certainty. So even if climate change and ocean levels behave exactly as climate models now predict over the next century, most scientists will still be loathe to state unequivocally that greenhouse gases were to blame. There will always be at least a tiny sliver of uncertainty.
The question is what you do with that uncertainty. You can use it as an excuse to do nothing, despite overwhelming evidence of trouble brewing on a global scale. Clearly, some are content to take that course. But that doesn’t mean it’s smart or responsible.