It's partly in response to the invasion of Ukraine. It did begin a bit earlier, though. You can see the dramatic rise in 2024 here: https://www.atlanticcouncil.org/blogs/econographics/whos-at-2-percent-look-how-nato-allies-have-increased-their-defense-spending-since-russias-invasion-of-ukraine/#:~:text=Sweden%20has%20also%20increased%20its,be%20prepared%20for%20the%20future.