When you’re looking up at the sky to observe the jet you heard flying overhead, you’ll often notice the wispy, white lines it leaves behind. What you may not know is that those white lines, known as contrails, are aviation’s biggest contributor to climate damage. The good news is that fixing it might be simple.

A new study published in Nature Communications indicates that making small detours around parts of the sky where those contrails form could be the solution.

Smarter flight paths may make the flights slightly longer, which uses more fuel, but it’s only minimal. The tradeoff: There will be far less heat trapped without the contrails.

Under the Paris Agreement, the world aims to keep the global temperature increase under 1.5 degrees, pre-industrial revolution, 2 degrees at the most. But we’ve already spent far too much of that allowance and we will soon be over target.

If we get started soon (by at least 2035), we could save 9 percent of the remaining budget by 2050. This means instead of reducing emissions, we stop adding heat right now.

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