We show that the water savings that plants experience under high CO2 conditions compensate for much of the effect of warmer temperatures, keeping the amount of water on land, on average, higher than we would predict with common drought metrics, and with a different spatial pattern. The implications of plants needing less water under high CO2 reaches beyond drought prediction to the assessment of climate change impacts on agriculture, water resources, wildfire risk, and vegetation dynamics.

Changes in the hydrology of high-altitude catchments may have major consequences for downstream water supply. Based on model projections with a higher spatiotemporal resolution and degree of process complexity than any previous intercontinental comparative study, we show that the impacts of climate change cannot be generalized. These impacts range from a high climatic sensitivity, decreasing runoff, and significant seasonal changes in the Central Andes of Chile to increasing future runoff, limited seasonal shifts, but increases in peak flows in the Nepalese Himalaya.

The number of refugees displaced by civil conflict or natural disasters is on the rise. Economic impacts of refugees on host countries are controversial and little understood, because data have not been available and the question of refugee impacts does not lend itself to conventional impact evaluation methods. We use a unique Monte Carlo simulation approach with microdata from refugee and host-country surveys to obtain the first estimates of refugee camps’ impacts on surrounding host-country economies and to compare impacts of cash versus in-kind refugee aid.

Ecological scaling laws are intensively studied for their predictive power and universal nature but often fail to unify biodiversity across domains of life. Using a global-scale compilation of microbial and macrobial data, we uncover relationships of commonness and rarity that scale with abundance at similar rates for microorganisms and macroscopic plants and animals. We then show a unified scaling law that predicts the abundance of dominant species across 30 orders of magnitude to the scale of all microorganisms on Earth.

Atmospherically transported dust from the Saharan desert provides pulses of biologically important nutrients, including iron, to ocean surface waters. The biological response to these ephemeral events is not fully known, especially among the heterotrophic microbial community. Here we use the well-characterized Vibrio genus as a model for heterotrophic bacterial response. We demonstrate that Saharan dust nutrients, deposited in tropical marine waters, can promote Vibrio bloom formation and suggest that dust-associated iron is an important driver of Vibrio population dynamics.

What would extensive fishery reform look like? In addition, what would be the benefits and trade-offs of implementing alternative approaches to fisheries management on a worldwide scale? To find out, we assembled the largest-of-its-kind database and coupled it to state-of-the-art bioeconomic models for more than 4,500 fisheries around the world. We find that, in nearly every country of the world, fishery recovery would simultaneously drive increases in food provision, fishery profits, and fish biomass in the sea.

Although black carbon (BC) represents a key short-lived climate forcer, its direct radiative forcing remains highly uncertain. The available results from available studies of absorption enhancement of BC particles during atmospheric aging are conflicting. Using a novel environmental chamber method, we have, for the first time to our knowledge, quantified the aging and variation in the optical properties of BC particles under ambient urban conditions representative of developed and developing countries.

We present the first, to our knowledge, estimate of global sea-level (GSL) change over the last ∼3,000 years that is based upon statistical synthesis of a global database of regional sea-level reconstructions. GSL varied by ∼±8 cm over the pre-Industrial Common Era, with a notable decline over 1000–1400 CE coinciding with ∼0.2 °C of global cooling. The 20th century rise was extremely likely faster than during any of the 27 previous centuries.

The end-Permian mass extinction not only decimated taxonomic diversity but also disrupted the functioning of global ecosystems and the stability of biogeochemical cycles. Explaining the 5-million-year delay between the mass extinction and Earth system recovery remains a fundamental challenge in both the Earth and biological sciences. We use coupled records of uranium concentrations and isotopic compositions to constrain global marine redox conditions across the end-Permian extinction horizon and through the subsequent 17 million years of Earth system recovery.

Reservoirs of infectious HIV-1 persist despite years of combination antiretroviral therapy and make curing HIV-1 infections a major challenge. Most of the proviral DNA resides in CD4+T cells. Some of these CD4+T cells are clonally expanded; most of the proviruses are defective. It is not known if any of the clonally expanded cells carry replication-competent proviruses. We report that a highly expanded CD4+ T-cell clone contains an intact provirus.