Climate change? Maybe

LITTLE ROCK — Can you blame the scorching weather on climate change? Not really. Or at least not yet.

In a National Oceanic and Atmospheric Administration report released earlier this month, researchers attempted to determine how much they could attribute six extreme weather events last year to human-caused global warming. Even now, months on, some experts worry that drawing conclusions is precipitous. Figuring out what caused a flood in Thailand or a drought in Texas is hard. Doing it quickly is harder.

The upshot? Anyone who, in the midst of a hurricane here or a heat wave there, simplistically blames them on greenhouse-gas emissions is wrong. But it’s also wrong to blame all extreme events on forces beyond human control.

Recurring climate patterns such as El Niño and La Niña can influence extreme weather. So can chance fluctuations in a massive, complicated Earth system. But natural variability doesn’t mean human activity hasn’t been playing an increasing role in the formation of extreme events, or in the scale of the resulting damage. Most obviously, more people are living in environmentally precarious zones. Stripping land or degrading wetlands can leave humans more vulnerable to floods, as in Thailand, or hurricanes, as in New Orleans.

And the planet is certainly warming. Humans releasing heat-trapping gases into the atmosphere are almost certainly responsible for much, if not all, of that warming; the particular patterns of warming, comparison to the historical record, and the basic precepts of physics all indicate this. On average, more energy in the system probably increases the intensity or frequency of certain extreme weather events, such as very high temperatures, across the planet. Patterns emerge. In recent years, there have been more record-breaking heat events and fewer record-breaking cold ones.

So, while the science of attribution improves, what can you say the next time you’re suffering through a sustained heat wave? This is the sort of thing that will get more common across a warming world. That should be more than enough to spur Americans to demand action from their leaders.