
One day, if we get it right, and we’re lucky, humans will be able to look back and talk about ‘the carbon age’. Starting with the industrial revolution, and ending at the end of this century, well be able to count the total amount of carbon we released during the carbon age. And if we’ve successfully managed the tricky situation we’re in, that amount will be less than 1 trillion tonnes.
According to new research, that’s the limit on what we can burn, ever, as a species, without severely messing up the planet. If we burn more than a trillion tonnes, well probably be too busy dealing with the effects of climate change to spend much time looking back into history. Normally, we talk about targets for reducing emissions – for NZ to do its bit globally we need to reduce our emissions here by 40% by 2020. But in a paper in the science journal Nature, a group of researchers decided to describe how emissions have to change in another way – in terms of a ‘carbon budget’.
So what is a carbon budget, exactly?
Broadly, once carbon is in the atmosphere it stays there for centuries. How hot the planet gets is controlled by the total amount of carbon dioxide in the atmosphere – not how much were emitting at the moment. So, for a temperature rise of 2 degrees, there’s a total amount of carbon we can put into the atmosphere. If you like, it’s a carbon budget to buy us 2 degrees of warming.
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