Dec 16, 2009
AGU update: US stock market believes in climate change
Although public scepticism about climate change appears to be on the increase, it looks like the stock market is paying attention to the phenomenon. Since the mid-1990s, stocks in large energy companies have fallen in response to announcements by NASA about record temperature results. That's according to Jesse Anttila-Hughes of Columbia University, US, at the American Geophysical Union Fall Meeting in San Francisco.
Anttila-Hughes believes traders saw NASA's news as adding to the scientific evidence about climate change and increasing the probability that we'll need to act to cut greenhouse gas emissions, something that is potentially problematic for the carbon-intensive energy industry.
NASA's announcements of years that had seen record high global temperatures led to drops in share values of around four per cent, wiping out about $3 billion in total each time. Share prices began to respond to each piece of news almost immediately.
Ice shelf collapses, in contrast, tended to cause energy company stocks to rise by roughly three per cent; this could be because investors link such collapses with reduced sea ice cover and greater opportunities for access to oil and gas beneath the poles. It seems people believe these changes will affect companies positively before the detrimental effects for the energy business of restrictions on greenhouse gas emissions kick in.
The study looked at stocks in energy companies included in the S&P 500 index of businesses traded in the US that have a market capitalization of $5 billion or more. The large size of these companies meant that they were all involved in fossil fuels in some form. Stocks in each business were traded 6.5 million times per day on average, so numerous traders were involved in the decision-making that set the share price. Anttila-Hughes reckons this means that the traders could be considered to be acting in the same way as the general public.
Looking at share prices could be a good way of finding out what the public really thinks on topics such as climate change, he believes. In contrast to opinion polls, when stating your opinion doesn't cost anything, share choices directly affect your wallet so you're more likely to reveal what you really feel. "Talk is cheap but you need to take it with a grain of salt," he said.