Geoscience Reference
In-Depth Information
however, given the evidence, and in the worst case scenario, where considerably greater temperature
rises occur, Earth will, as NASA's James Hansen bluntly put it, resemble “another planet.”
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question boils down to this: Are we willing to roll the dice, with Earth lying in the balance? And is it
within our rights to imperil future generations should we be wrong?
Given the wealth of scientific evidence amassed by the mid-1990s, one might rightly wonder
how there could be a viable opposing position on controlling our carbon emissions. It was already
difficult for any scientist to credibly argue that Earth wasn't warming, or that there was no impact on
our climate by human activity (though a few still did, nonetheless, and still do). However, even
among those who accepted the facts of global warming, there was still an awareness that much
uncertainty exists, as we have seen. How much warming would there be? How much of the warming
that had occurred could we confidently attribute to human activity? And precisely what impacts
would the forecasted changes have on our daily lives? These were still wide-open questions. And
while we continue to refine our understanding of climate change, many of these questions remain open
to this day.
Taking steps to reduce emissions to levels that would avoid breaching 450 ppm would have
been far easier in 1995 than it is now, given that we have emitted more than 100 billion tons of
carbon into the atmosphere in the meantime. But even then, it would have been challenging and
potentially costly. Those opposed to action could point to that uncertainty for justification. Why
should we engage in potentially expensive measures to reduce greenhouse gas emissions, they could
say, when the benefits are unclear? The impacts of continued fossil fuel burning in the decades ahead
might be mild, some asserted; they might even be favorable. Back when I was working on my Ph.D., I
would sometimes encounter such an argument from friends and acquaintances who knew that my
research, at least vaguely, had something to do with the topic of global warming.
In fact, I wasn't completely unreceptive to this argument at the time. It was at least an honest, if
somewhat flawed, line of reasoning. The flaw, as I would gently point out, is that the logic could just
as easily work the other way. What if the problem was actually worse than our current prevailing best
estimates? What if the true response of the climate instead lay at the high end of the uncertainty range?
The effects in that case could be catastrophic and the costs to civilization and our environment
incalculable. In fact, the argument was not my own. I had seen it advanced by Stanford University
climate scientist Stephen Schneider in an article that had left an impression on me. Schneider had
because we believe our homes are going to burn down. We purchase it because if our house did burn
down, it could ruin our lives. We purchase fire insurance to hedge against a perhaps quite low-
probability, but undeniably catastrophic, potential outcome. It is useful to think of climate change
mitigation the same way. I find Schneider's analogy as compelling today as I did then.
But even in the mid-1990s, as the scientific case had become persuasive, some critics weren't
content to engage in the worthy debate to be had over climate change policy, cost-benefit analysis,
and risk management. They were instead intent on preempting that debate by continuing to argue that
climate change itself, if not a massive and deliberate hoax, was based on bad science. Perhaps they
were afraid that general acceptance of the facts behind global warming and the risks it poses would
lead the public to demand action to protect the future. Whatever their motive, they sought to deny the
science altogether.
