What’s going to change, exactly?
When we talk about climate change, it’s important to distinguish between climate and weather. When temperatures can swing by ten or twenty degrees from one day to the next, 3.5°F of warming doesn’t sound like something to get too excited about. But those day-to-day temperature changes are examples of weather, not climate. Climate can be thought of as the parameters within which a place’s weather operates—in other words, a place’s climate tells you what kind of weather is normal for that area. For example, Seattle, WA, has a much different climate than Phoenix, AZ. Seattle is relatively wet, with mild temperatures that rarely hit either an extreme high or an extreme low. Phoenix, on the other hand, is very dry, averaging just over eight inches of rain a year, and has temperatures that frequently climb above 110°F in the summer. Temperature is not the only factor that determines an area’s climate—elevation, topography, and proximity to water also have an effect—but it is one of the most important.
In that context, 3.5°F is actually a fairly large amount of warming. It’s the difference between living in Milwaukee, WI, and Akron, OH, 150 miles to the south2. It’s not that it never gets colder in Akron than in Milwaukee—it’s pretty much guaranteed to happen at least a few times a year—but in general Akron tends to be the warmer of the two cities. They have different climates. The difference between Athens, GA, and New York, NY, is even more obvious. Athens is about 7°F warmer than New York2. If you flew from one to the other, you would probably notice the difference as soon as you stepped off the plane. New Yorkers would be understandably concerned if their city suddenly had Athens’ climate, and vice versa.
Saying that the earth will be 3.5°F to 7°F warmer by 2100 can seem a bit abstract. Another way to visualize it would be to imagine that the town where you live is moving two to four miles south every year. You’d hardly notice the change at first, but by the end of the century, when your town is 200- 400 miles further south than it is today, you would definitely be able to tell that, overall, its climate had gotten warmer.
Climate change doesn’t mean that it will never be cold again. There will still be winter, no matter how warm the planet gets. What climate change does mean is that warm days will be a little warmer, and cold days a little less cold. The day-to-day effects won’t be dramatic, but as with everything else related to climate change, a lot of small changes can add up to something big.