The Curve

How Science can save the World

Let's go on a journey half way around the world . . . to the Mauna Loa Observatory, on top of a volcano in Hawaii. As well as being a really nice place to visit, Mauna Loa is the home of the Keeling Curve.

The Keeling Curve is a graph which shows how the amount of carbon dioxide in the atmosphere is going up year after year. Every day, in the observatory, scientists measure the concentration of carbon dioxide in the atmosphere. They have to make these measurements here, in the middle of the Pacific Ocean, they because it's far away from human contamination . . . smoking isn't allowed in the laboratory!

David Keeling was the first person to do this in a systematic and accurate way; he plotted the measurements on a graph and made the curve which bears his name. Here it is . . .

The graph shows the concentration of carbon dioxide in the atmosphere in units of parts per million, or ppm for short. Today, when I checked, it was 397.8 ppm. That doesn't sound much . . . but at the beginning of the century it was 369 ppm; when Henry shot himself in his chapel it was only 286 ppm. This year it will exceed 400 ppm for the first time in human history.

The big thing you need to know about the Keeling Curve is that it keeps going up, at an ever increasing rate. And we know the reason why: it's. caused by burning fossil fuels such as coal, gas and oil. All that carbon was locked up for millions of years, and we've let it go in less than 100.

So what's to worry about? For one thing, we know that this increase in carbon dioxide has caused the earth to warm up by about 0.85 °C over the last 120 years. Doesn't sound much does it, but think about how large the earth is and the amount of energy required to cause even a small amount of warming, and you begin to realise that it can have really big effects.

That's not the only thing; it's causing the oceans to become more acidic at an unprecedented rate, and that unbalances the chemical equilibrium that allows most sea creatures to grow.

We aren't 100% sure how all this will turn out, but we're sure enough that it makes sense to do something about it; just like you aren't sure that you'll be involved in a head-on collision in your car . . . but you still put the safety belt on.