In a recent interview a candidate for the US presidency remarked that "there hasn't been a day on Earth when the climate hasn't changed".
If you're not a scientist, it might seem hard to disagree with that. Many people think weather and climate are the same thing. Instead, they are quite different concepts.
Weather is what we feel every day. There are hot days, cold days, rainy days, sunny days, and everything between. Climate is the weather we feel over a long time, at least three decades. It can't 'change' in a day.
Confusion between climate and weather is common. This misunderstanding is often used in arguments denying climate change. One example is the 'pause' in global warming seen in the first decade of the 2000s. If we think about how our climate is changing, this doesn't tell us much. Our Earth's climate changes over thousands of years. Ten years is a tiny sliver to be basing conclusions on.
I say this even though we know the scientific reasons behind the 'pause'. Oceans are taking in more energy, making them warmer but not the air (for now!). Trade winds, which push huge amounts of air around the world, slowed down. Recent data shows there has not been any pause in warming.
The picture climate change paints is a steady rise in temperatures. The best analogy is an escalator (see below). When we’re standing on a step, temperatures go up and down, and it seems like warming isn’t happening. This isn’t true. Global warming is the escalator gradually taking us higher and higher.
Some years the weather won't seem hotter than the previous years. It might even be colder. But the fact is we’ve been on the escalator for more than a century. And it’s getting faster.
The higher up we go, the warmer the world will be on average. So it shouldn't be surprising that 2015 was the warmest year on record (136 years). The three warmest years have also occurred in the past five years. In the US West Coast, Eastern Europe, and parts of Brazil, the average temperature was about 2.5C warmer this year. Winter was particularly warm.
There are behind the scenes actors which explain why 2015 was so hot (a strong El Nino event). I'll save the physics behind El Nino for another day. The basic conclusion is clear, though. If we are true to ourselves and look at the facts, the world is getting warmer. We also know who the culprit is: us.
There is the famous tale of a group of frogs in a pot, about to be cooked. The water starts off lukewarm. "This isn't bad, but a few degrees more wouldn't hurt!” said one. Soon it gets warmer, like a hot tub. "This is great!” thought the frogs. They got used to the water, and relaxed. But it kept getting hotter and hotter. Soon it became uncomfortable, but none of the frogs wanted to say anything. "OK this is getting pretty bad, but it seems the others are fine", thought the frogs as they all stayed quiet. As the temperature crept close to boiling it became unbearable, and they all tried to swim out. But it was too late, and the frogs didn't make it.
A good resolution for the new year? Let's not be the frogs.
Tim Dobermann is the Project Lead for Research & Policy at SDSN Youth. He is a Country Economist for the International Growth Centre and has participated widely in both research and in policy dialogues pertaining to economic development and climate change. He holds a postgraduate degree in economics from the London School of Economics (LSE).