Why Two Degrees Matter

Even small changes have giant effects on people and the natural world that sustains us.

Severe problems are coming unless we limit global warming to +2^◦C above pre-industrial era temperatures. And, since the stakes are so high, scientists highly recommend we try to keep it to only +1.5^◦C.

Bad news: That +1.5^◦C goal is already starting to elude us – and not just for a day or two. The 12 months ending January 2024 showed 1.52^◦C of warming vs the 1850-1900 average.

As this chart shows, the trend has been steadily upward since the 1970s. The average can vary quite a bit from year to year due to El Nino events, solar activity, volcanoes, etc., but it keeps rising. We’re running out of wiggle room even as global carbon emissions keep rising.

(Chart: BBC)

We are entering the danger zone. Yet many folks still think two degrees is no big deal. (Fellow Americans, please note 2^◦ Celsius is equal to 3.6^◦ on the Fahrenheit scale.)

Two degrees is enough to matter. We all know this already. Our bodies can tell the difference. Ever gone to bed and then feel hot or cold? I’ll bet so. And I’ll bet adjusting your thermostat just one or two degrees restored your comfort.

If the human body is that temperature-sensitive, it should be easy to believe the planet is, too.

Nor is it just humans. Animals sense the difference, too. We can actually calculate the air temperature from how fast crickets chirp. Temperature changes tell many species when to reproduce, go dormant or migrate. Abnormal heat can send disease-carrying insects like mosquitos to places where they didn’t previously go.

(Image: Pixabay)

Fish know it, too. They spend their lives swimming around in search of optimal conditions, part of which is temperature. They can move a long way if something, like global warming, changes the sea temperature even slightly above or below their ideal. This is a growing problem for the fishing industry and an even bigger problem for marine life that can’t easily relocate, like coral. Those species can die, which has other not-so-good effects.

It also matters which degrees are changing. A three-degree change at room temperature is one thing. Going from 30^◦F to 33^◦F is different. That “small” amount of warming turns frozen ice into liquid water.  When this happens in your freezer, it makes a small mess. If it happens in Antarctica? A much bigger mess.

The atmosphere itself is temperature sensitive, too. Warmer air holds more moisture – about 7% more per each degree Celsius. This affects the weather, making storms more intense, but that’s not all. The Earth has a fixed total amount of water. If higher temperatures keep more water suspended in the air, it means less water at ground level where humans can use it. This isn’t good, as people in drought-stricken regions can attest.

See the problem? Even small temperature changes can have giant effects on us and the natural world that sustains us.

That’s why climate change, even just 2^◦C, is going to hurt.