Can science predict the future?

In 2009, a 6.3-magnitude earthquake struck L’Aquila, Italy, killing more than 300 people. Six Italian seismologists were later convicted of manslaughter for failing to adequately warn the citizens of L’Aquila of the deadly earthquake. L’Aquila had experienced a series of small tremors in the months leading up to the 6.3-magnitude quake causing the people to wonder whether they should evacuate.

The scientists were not convicted of failing to predict the earthquake but of failing to communicate the risks. But the scientists did communicate the risks accurately to government officials, however it was left to a civil protection official with no specialist knowledge in seismology to communicate this to the general public. His statement to the public was, “The scientific community tells us there is no danger, because there is an ongoing discharge of energy. The situation looks favourable.”

It is debatable whether the seismologists should have stepped in at this point to correct what was an incorrect assessment of the danger. But I don’t believe a charge of manslaughter is warranted in this case.  It seems to me that scientists get vilified when they express the risks and vilified when they don’t.

Climate scientists are vilified by people who have no specialist knowledge in climate science simply because they express the risks of climate change to the public. One of the most vilified of all climate scientists is James Hansen, ex-NASA scientist. To me, James Hansen seems like a nice person. I’ve watched some of his lectures online, seen him interviewed on TV and read some of his papers. As far as I know, he’s never ripped any limbs off puppies or pulled wings off a bird, or abused small children, but some of the disparaging remarks I’ve read about him would leave you wondering whether he has.

Could it be because his predictions have been wildly inaccurate? Even if they had, I don’t believe this is justification for any abuse. At most, it might lead us to give less weight to his findings.

It’s possible to go and read James Hansen’s very first paper on the subject. It’s called Climate Impact of Increasing Atmospheric Carbon Dioxide and was published in 1981. Here’s what he predicts:

It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980’s. Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.

I can’t comment on his prediction of drought-prone regions in North America and Asia (maybe someone else can?), but all his other predictions are happening now. He predicts that the Northwest passage will open sometime in the 21st century. It is looking more and more like it will happen in the early 21st century. He also predicts a rise in temperature of more than 2°C by the end of this century in all scenarios except no growth in fossil fuel usage (from 1980 levels) and coal phaseout. As fossil fuel usage has accelerated since 1981 we are on course to exceed a 2°C warming by the end of this century.

Far from being wildly inaccurate, James Hansen’s very first paper on the subject was remarkably correct. I have come to the conclusion that he is so passionately hated by people who deny the existence of global warming simply because they don’t like what he has to say. Perhaps the public officials of L’Aquila, Italy felt the same way when the risks of a large earthquake were communicated to them and so they chose to edit the warnings before passing them on to the general public.

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