By Andy Miller
A question I often hear is whether a particular weather event or condition is caused by climate change, and my answer is almost always no. You can’t say that a specific tornado, torrential downpour or 100 degree plus day is caused by climate change.
So if the answer is that the weird weather isn’t caused by climate change, then why are we so concerned? Before we get to that, let’s remember what climate is. Climate is the long-term average of the weather. As has been said, “Climate is what we expect, weather is what we get.”
Climate change means that the expected weather patterns are no longer what they used to be—that is, the long-term average weather is changing. While the climate has changed in the past, now we are seeing changes that can only be explained by the rising level of greenhouse gases caused by human activities such as burning fossil fuels and cutting down forests.
The question about whether climate change has “caused” a particular weather event is like asking whether a baseball team scored on a specific play because it has a better win-loss record than its opponent. The win-loss record doesn’t determine the outcome of an individual play, but all those individual plays determine the win-loss record. Climate is like a team’s win-loss record—it doesn’t determine a specific weather event, but rather all the individual events determine the weather patterns that make up climate. And with climate change, it’s becoming clearer that the losses are starting to stack up against us.
If climate doesn’t determine a specific weather event, why do we often hear that climate change is affecting the weather? What we need to remember is that this is just shorthand for what the science is really telling us. What the science is really saying is, “higher levels of greenhouse gases in the atmosphere are trapping greater amounts of solar energy, which is causing a change in how the atmosphere and oceans circulate, the amount of moisture in the air, and the amount of ice, all of which are causing changes to weather patterns across the globe.” That’s a lot to say, so you can see why we simply talk about climate change as the cause of these impacts.
The “impacts of climate change” (which we can use now that we know what that’s really saying) are discussed in considerable detail in the new National Climate Assessment that will be published in the coming weeks. The assessment explains what changes we are seeing now, and what we expect to see in the coming years. It shows why we’re concerned about climate change and its impacts. And most importantly, it explains why we need to take action now on climate change.
We are only starting to see the impacts of climate change. To turn to our sports analogy again, it’s like we’re at the start of a new season. It’s often hard to see which team is going to be the best after only a few games. But as the season progresses, it will be easy to see which teams have prepared well by bringing in the best players and training hard before the season starts.
Likewise, taking action on climate change now means that we will be much better prepared to meet the challenges we face in the coming years. EPA is taking action now on climate change, and that includes EPA’s scientists and engineers. They are teaming up to develop the scientific information and tools that will help the nation and the world prepare a winning game plan to respond to climate change.
A team that waits to begin training until after it falls behind in the standings has no chance of winning, and waiting to act on climate change until the impacts are even worse is also a losing strategy.
About the Author: Andy Miller is the Associate Director for Climate in EPA’s Air, Climate, and Energy Research Program that conducts research to assess the impacts of a changing climate and develop the scientific information and tools to act on climate change.