When the gavel came down for the final time at the climate summit in Paris on 12 December, representatives from 195 countries erupted into cheers. They had approved a landmark plan to combat climate change after two weeks of gruelling negotiations. The agreement commits most countries to reduce their greenhouse-gas emissions, while seeking to protect low-lying islands from rising seas and helping poor nations to develop their economies without relying on cheap, dirty fossil fuels.

The response of the Greenland Ice Sheet (GIS) to changes in temperature during the twentieth century remains contentious1, largely owing to difficulties in estimating the spatial and temporal distribution of ice mass changes before 1992, when Greenland-wide observations first became available2. The only previous estimates of change during the twentieth century are based on empirical modelling3, 4, 5 and energy balance modelling6, 7.

The devastating magnitude-7.8 earthquake that struck Nepal in April caused surprisingly few landslides, researchers say — confirming the early impressions of scientists who raced to map collapsed terrain in the quake’s aftermath. However, there is still hot debate over just how severe the event’s impacts were.

Intensification of the hydrologic cycle is a key dimension of climate change, with substantial impacts on human and natural systems1, 2. A basic measure of hydrologic cycle intensification is the increase in global-mean precipitation per unit surface warming, which varies by a factor of three in current-generation climate models (about 1–3 per cent per kelvin)3, 4, 5. Part of the uncertainty may originate from atmosphere–radiation interactions. As the climate warms, increases in shortwave absorption from atmospheric moistening will suppress the precipitation increase.

It has been suggested that carbon starvation, owing to reduced availability of non-structural carbohydrates (NSCs), is an important contributor to tree mortality during drought in tropical rainforests; however, data from the world’s longest-running experimental drought study presented here show no evidence of carbon starvation, and instead the researchers conclude that impaired water hydraulic processes (involving the transport of water from soil to leaf) have a more important role in triggering tree death from long-term drought.

Recent work has suggested that sections of the West Antarctic ice sheet are already rapidly retreating, raising concerns about increased sea-level rise; now, an ice-sheet model is used to simulate the mass loss from the entire Antarctic ice sheet to 2200, suggesting that it could contribute up to 30 cm of sea-level rise by 2100 and 72 cm by 2200, but is unlikely to contribute more.

Success at the latest climate talks will be a recognition by the world’s nations that incremental change will not do the job, says Johan Rockström.

A furious debate that is raging in Brazil pits the nation’s largest university against hundreds of cancer patients who want access to a compound that some have branded a miracle cure. (Editorial)

Original Source

Leaders must come together on a solid agreement at the United Nations climate conference — and then get to work at home by meeting commitments and finding new ways to reduce emissions. (Editorial)

Original Source

Marine sediments from the North Pacific document two episodes of expansion and strengthening of the subsurface oxygen minimum zone (OMZ) accompanied by seafloor hypoxia during the last deglacial transition. The mechanisms driving this hypoxia remain under debate. We present a new high-resolution alkenone palaeotemperature reconstruction from the Gulf of Alaska that reveals two abrupt warming events of 4–5 degrees Celsius at the onset of the Bølling and Holocene intervals that coincide with sudden shifts to hypoxia at intermediate depths.