Detection and attribution of human influence on regional precipitation

Understanding how human influence on climate is affecting precipitation around the world is immensely important for defining mitigation policies, and for adaptation planning. Yet despite increasing evidence for the influence of climate change on global patterns of precipitation, and expectations that significant changes in regional precipitation should have already occurred as a result of human influence on climate, compelling evidence of anthropogenic fingerprints on regional precipitation is obscured by observational and modelling uncertainties and is likely to remain so using current methods for years to come. This is in spite of substantial ongoing improvements in models, new reanalyses and a satellite record that spans over thirty years. If we are to quantify how human-induced climate change is affecting the regional water cycle, we need to consider novel ways of identifying the effects of natural and anthropogenic influences on precipitation that take full advantage of our physical expectations

Global lake responses to climate change

Climate change is one of the most severe threats to global lake ecosystems. Lake surface conditions, such as ice cover, surface temperature, evaporation and water level, respond dramatically to this threat, as observed in recent decades. In this Review, we discuss physical lake variables and their responses to climate change. Decreases in winter ice cover and increases in lake surface temperature modify lake mixing regimes and accelerate lake evaporation. Where not balanced by increased mean precipitation or inflow, higher evaporation rates will favour a decrease in lake level and surface water extent. Together with increases in extreme-precipitation events, these lake responses will impact lake ecosystems, changing water quantity and quality, food provisioning, recreational opportunities and transportation. Future research opportunities, including enhanced observation of lake variables from space (particularly for small water bodies), improved in situ lake monitoring and the development of advanced modelling techniques to predict lake processes, will improve our global understanding of lake responses to a changing climate

Beyond equilibrium climate sensitivity

ISSN:1752-0908ISSN:1752-089

The Mediterranean is getting saltier: From the past to the future

The Mediterranean region is getting drier. Evaporation has been steadily increasing over the last few decades driven by the rapid surface warming implying an increase of latent heat loss from the sea surface. A long-term decrease of river freshwater discharge has been also observed since the early 1960s, reflecting the impact of both river damming and recent climate change. As a result of the net evaporation increasing rate, the salt content of the basin has been also strongly increasing over the last four to five decades with this salinification signal rapidly travelling from the surface into the deep layers via the intense Mediterranean overturning circulation. Long-term increases were also observed in the salinity of the Levantine Intermediate Water layer throughout the basin, which strongly influences cold-water coral habitats and distribution. Climate models predict that the present warming and salinification trends will be accelerated over this century and they are expected to have strong impacts on marine ecosystems and biodiversity