Climate Geo-engineering study on sulphate injection shows Hydrological disruption to rain and severe drought

While politicians have effectively dithered on robust action to reduce greenhouse gas emissions over the last 20 years we are hearing more about geo-engineering proposals to moderate rising temperatures. But the latest study from the University of Reading scientists modelling solar radiation management, and in particular atmospheric aerosol injection - one of the easiest geo-engineering proposals to do at large scale - says such a project would result in a major decrease in tropical rainfall and an increase in drought in many regional areas.

The Reading University study concentrated on the consequences on geo-engineering methods to change the solar radiation reaching the earth: through mirrors above the atmosphere; and injecting sulfate aerosols into the atmosphere to reflect solar radiation. The first could prove hideously expensive and is at the moment impractical, but the second method is quite achieveable at reasonable cost.

The study - Weakened tropical circulation and reduced precipitation in response to geoengineering (Full paper) - looks at aerosol injection in particular and the projected impacts. It was published in Environmental Research Letters.

Related: Yale Environment360: Solar Geoengineering: Weighing Costs of Blocking the Sun’s Rays (9 Jan 2014)

Alberta Floods highlight a more active water cycle with climate change

An intense rainfall and storm event on June 20-21 has caused widespread flooding in the Canadian province of Alberta, encompassing much of the southern portion of the province including Canada's fourth largest city of Calgary. It is the worst flooding event in Alberta's recorded history, highlighting the more active hydrological cycle with climate change.

Over 120,000 people across the region were evacuated, 75,000 in Calgary (7% of the population), many now returning to flood damaged homes and businesses to start the clean up.

I am not going to say climate change caused the flooding. Clearly natural weather variability still plays a significant part in extreme weather events. But the reality is we have warmed the atmosphere and changed the base climate from which all extreme weather events are generated from. We are now living with weather in a more active hydrological cycle resulting in more frequent and intense storm events with a capacity to cause greater flooding.

Global Warming intensifying Global Water Cycle by double current climate model projections

New research into ocean salinity levels has revealed a strong global water cycle intensification during the period of 1950 to 2000. The researchers report the rate of change in the global water cycle is double the rate projected by current-generation climate models. The study found "robust evidence of an intensified global water cycle at a rate of about eight per cent per degree of surface warming," said study co-author Dr Durack, a post-doctoral fellow at the Lawrence Livermore National Laboratory in the US.