The observations contain a lot of «noise», which causes annual variation that is not a function of CO2 concentration. (skepticalscience.com)
It also revealed annual variations in local gravity due to the natural storage and depletion of water during rainy and dry seasons in different parts of the world. (discovermagazine.com)
Are you implying that weather is wildly unstable and unpredictable, and that for instance annual variations in sea ice are predictable and smooth? (mustelid.blogspot.ru)