We evaluated the response of the Earth land biomes to drought by correlating a drought index with three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, treering growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of the water deficit (i.e., the drought timescale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions have mechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ from those operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long timescales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change. drought impacts | NDVI | drought adaptation | Standardized Precipitation Evapotranspiration Index | drought index

Wind power is a rapidly growing alternative energy source to achieve the goal of the Paris Agreement under the United Nations Framework Convention on Climate Change, to keep warming well below 2 •C by the end of the 21 st century. Widely reported reductions in global average surface wind speed since the 1980s, known as terrestrial stilling, however, have gone unexplained and have been considered a threat to global wind power production. Our new analysis of wind data from in-situ stations worldwide now shows that terrestrial stilling reversed around 2010 and global wind speeds over land have recovered most of the losses since the 1980s. Concomitant increased surface roughness from forest growth and urbanization cannot explain prior stilling. Instead we show decadal-scale variations of nearsurface wind are very / quite likely caused by the natural, internal decadal ocean/atmosphere oscillations of the Earth's climate system. The wind strengthening has increased the amount of wind energy entering turbines by 17 ±2% for 2010-2017, likely increasing U.S. wind power capacity by 2.5%. The increase in global terrestrial wind bodes well for the immediate future of wind energy production in these regions as an alternative to fossil fuel consumption. Projecting future wind speeds using ocean/atmosphere oscillations show wind turbines could be optimized for expected wind speeds, including small and large speeds, during the productive life spans of the turbines. Reports of a 8% global decline in land surface wind speed (~1980 to 2010) have raised concerns about output from future wind power 1-5. Wind power varies with the cube of wind speed (u) 6. The decline in wind speed is evident in the northern mid-latitude countries where the majority of wind turbines are installed including China, the U.S. and Europe 1. If the observed 1980-2010 decline in wind speed continued until the end of the century, global u would reduce by 21%, halving the amount of power available in the wind. Understanding the drivers of this long-term decline in wind speed is critical not merely to maximize wind energy production 9-11 but also to address other globally significant environmental problems related to stilling, including reduced aerosol dispersal, reduced evapotranspiration rates, and adverse effects on animal behavior and ecosystem functioning 1,3,4,12. The potential causes for the global terrestrial stilling are complex and remain contested (e.g.,