More plants and longer growing seasons in northern latitudes have converted parts of Alaska, Canada and Siberia to deeper shades of green, probably related to global carbon uptake. But increased carbon absorption by plants in the Arctic is being offset by a corresponding decline in the tropics. With rising global temperatures the atmosphere in the tropics (where plant productivity is limited by the availability of water) has become drier. Recent increases in drought and tree mortality in the Amazon rainforest are one example, and productivity and carbon absorption over land near the equator have gone down over the same time period as Arctic greening has occurred, canceling out any net effect on global productivity.
www.sciencedaily.com/releases/2020/12/201218131844.htm