Net Zero by 2050 has become a focal point for corporations and governments. Distilling climate change into a simple deadline has been helpful, and the number of companies who have signed up for realistic trajectories to get to Net Zero is cause for optimism.<\/p>\n\n\n\n
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The reality is somewhat more complicated. Because CO2<\/sub> accumulates in the atmosphere <\/span>1<\/sup><\/a><\/span>, concentrations today are determined by the cumulative emissions over the last 10’000 years. When we hit Net Zero, all of the gas we’ve emitted along the way won’t simply vanish: it’s a legacy we’re going to live with for a long time. We’ve been filling up a big bathtub and it won’t empty the moment we turn off the tap.<\/p>\n\n\n\n <\/p>\n\n\n\n This means that it’s not only the destination<\/em> of Net Zero that’s important, but the journey. How many tonnes of CO2 <\/sub>we emit on the route to Net Zero will determine how much warmer the world becomes. Returning to the bath tub: if we run the taps at full blast until 2050 and then turn them off, we’re going to end up with a much fuller tub than if we gradually reduce the flow. The exact date<\/em> that we hit Net Zero is less important than the journey we take to get there.<\/p>\n\n\n\n <\/p>\n\n\n\n To get a more intuitive sense of this, have a play with the graph below. I’ve fixed the destination – zero emissions by 2050 – but you’ll see that the shape of that journey makes a huge difference to the temperature rises that result <\/span>2<\/sup><\/a><\/span>.<\/p>\n\n\n\n <\/p>\n\n\n\n