If adaptive evolution cannot keep up with rapid climate change, populations and even species may decline or go extinct. Such adaptational lag is predicted, but evidence is scarce. We tested for lagging adaptation to warming climate in banked seeds of the annual weed Arabidopsis thaliana in common garden experiments in four sites across the species’ native European climate range. Genotypes originating in climates historically warmer than the planting site had higher relative fitness than native genotypes in every site.

Through an examination of shallow ice cores covering a wide area of the Greenland Ice Sheet (GIS), we show that the same mechanism drove two widespread melt events that occurred over 100 years apart, in 1889 and 2012. We found that black carbon from forest fires and rising temperatures combined to cause both of these events, and that continued climate change may result in nearly annual melting of the surface of the GIS by the year 2100.

Earth’s core is less dense than iron, and therefore it must contain “light elements,” such as S, Si, O, or C. We use ab initio molecular dynamics to calculate the density and bulk sound velocity in liquid metal alloys at the pressure and temperature conditions of Earth’s outer core. We compare the velocity and density for any composition in the (Fe–Ni, C, O, Si, S) system to radial seismological models and find a range of compositional models that fit the seismological data.