Category Archives: Climate Change

Heat wave, pt. 2

I wrote earlier that even a heat wave as pronounced as the one most of North America is now experiencing should not be taken on its own as evidence of global warming. I meant that this record breaking heat “proves” global warming no more than snow in Washington D.C. “refutes” global warming. Basically, I was making the “weather is not climate” argument, stressing the importance of the reams of weather data that climate scientists are using to predict global warming. But in an excellent column, Jocelyn Fong at Media Matters explains why this “weather is not climate” argument can’t be used interchangeably by climate advocates and deniers. I recommend you read the whole thing.

When climate advocates say “weather is not climate” during the winter, they are trying to communicate that weather variability doesn’t stop just because the planet is heating up on average. It’s crucial to note that they are saying this in response to those who claim a snowstorm or a cold snap refutes global warming. When you’re trying to overturn a theory that is based on long-term data, a single storm or weather event just won’t do. The burden of proof is higher. A cold snap doesn’t tell us much about climate, but a whole bunch of them would over time. The trends just aren’t going in that direction.

The record-breaking average temperatures of the past six months have followed a decade of historic average temperatures, so this current phenomenon is not a freak occurrence. But climate scientists have been extremely reluctant to tell the public that particular cases of extreme weather are evidence of the megatrend that is occurring. Instead, they try to communicate to decision makers through the very conservative reports produced by the IPCC, which rely on reams of data gathered since the 19th century and beyond.

But statistical analysis of millions of bits of data doesn’t really grip the human imagination the way a scorching hot summer can. Some research on this topic popped up in my twitter feed a few days ago.

From the paper (emphasis mine):

Studies that have examined opinion about the existence of global warming suggest that people’s values and political predispositions have a bigger impact than factual information on judgments about the nature and extent of the problem. Age, liberal ideology, pro-environment attitudes, and being nonreligious are associated with existence beliefs, while the effect of scientific knowledge about the causes and consequences of climate change is weak and inconsistent (Bord, O’Connor and Fisher 2000; Kellstedt, Zahran and Vedlitz 2008; but see Curry, Ansolabehere and Herzog 2007). People’s perceptions of the threat posed by global warming appear to be guided more by the polarized discourse of
political elites than by the scientific consensus affirming that climate change is taking place.

We hypothesize that an additional factor—the personal experience of local temperature variation—has an independent effect on attitudes about the existence of global warming.

For each 3.1° Fahrenheit that local temperatures in the past week have risen above normal, Americans become one percentage point more likely to agree that there is “solid evidence” that the earth is getting warmer… The size of the effect is substantial, comparable to the ceteris paribus differences in global warming beliefs by race, age, or education, and the effect increases in magnitude after longer periods of abnormal temperatures. The impact is short-lived, however, and therefore does not induce long-term attitude change.

So while the heat will affect attitudes about global warming in the short term, we shouldn’t bank on it to change the political environment. What we desperately need is a change in the public discourse, so that people can appreciate the changes they are seeing in their local weather within a broader context. Neither personal experience of extreme weather nor passive acknowledgement of scientific consensus is enough to get people to adjust their living patterns or expectations for the future. The talking heads on television can help the general population connect the dots between personal experience and abstract climate science. They can help us realize that as the climate changes, extremely hot summers like this one will become more likely and more common. When the media fails to point out that this hot weather is what the abstract concept of global warming actually feels like, people don’t change their attitudes or think about how prepared they are for a hotter, angrier planet.

Fung at Media Matters compares how the media contextualizes particular economic events within the broader frame of the national economy, but fails to do so when reporting on weather.

In December 2008 the Washington Post reported that AT&T and DuPont planned to lay off a combined 14,500 employees. The lead of the story said: “Need more proof that the recession is real? An onslaught of grim unemployment and layoff reports yesterday should dispel any lingering doubts.”

Was the recession the only force behind these job cuts? No. Other variables would be needed to explain why the layoffs were hitting these specific companies, at this time, and at this scale.  But the recession was the obvious background condition, the broader context that could not go unmentioned in a proper news report on the layoffs, and there was no hand-wringing about drawing the connection. The article didn’t caution that “No single bankruptcy or job cut can be definitively blamed on the recession.”

Back to the recession analogy. Imagine if, in 2009, President Obama spotlighted a company that was thriving to argue that the recession was over. Such a statement would not be taken seriously anywhere. Why? Because of the broader context — because of what we knew about the trends in employment, GDP, investment spending. By the same token, we know that by warming the climate, we’re making heat extremes more probable, and when we bring up climate change during a heat wave, it’s not to say that a specific heat wave is evidence of climate change — we have plenty of evidence in the long-term trends — it’s to say “this is what global warming looks like.” The alternative, refusing to recognize the symptoms of a disease we know we have, isn’t a smart approach, and it’s not good journalism.

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Heat wave

As Vancouver finally gets its first taste of summer, we can look to central Canada and the United States and feel fortunate that we’re not suffering from temperatures in excess of 40 degrees Celsius. Are the record-breaking temperatures evidence of global warming? I don’t think that’s really the question we should be asking. We can’t look at a single heat wave (even when it is as intense and as wide-ranging as what we’re seeing right now) and declare it proof of a global trend. No more than climate science deniers can claim that snow in Washington, D.C. disproves global warming. As convincing as this oppressive, sustained heat might seem, we can only find evidence of anthropogenic climate change in very large data sets — and by “we” I mean huge teams of climate scientists using number-crunching computers. I expect to see exactly this kind of finding in the next IPCC report.

The question we should be asking is, “If so many people have died this week from heat exhaustion and other heat-related causes, how ready for climate change are we?” The answer is “not at all”. We don’t have any reason to believe that North America’s electricity grid will be any more robust in the future. Hugely disruptive power outages are more likely in the coming decades, given that nobody seems willing to spend the money necessary to maintain existing energy infrastructure. And energy prices will rise, making it that much more difficult for the underclass to afford air conditioning, refrigerated food, fresh water, and literally every other modern amenity that keeps them alive.

Unfortunately, thinking about global warming in terms of dangerously hot days is far too narrow. It’s tragic that the old, the poor, and the infirm will die by the thousands in their poorly-insulated homes with no access to affordable medical care. But they’ll die in the middle of the winter, too, because of the general and catastrophic damage to the economy that climate change will inflict. Climate change (along with the energy crunch) will wreak havoc on world trade and food security. Mitigating the damage of sea level rise and extreme weather will suck away manpower and capital that could otherwise build sustainable housing, transportation, and medical facilities. The geographical range of tropical diseases will expand… the list of negative effects goes on. The fact is, runaway global warming is going to disrupt the economy so thoroughly that we can’t possibly anticipate all the indirect effects. But we can bank on who will suffer the most.

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