Climate change is likely to be more severe than some models have implied, according to a new study which ratchets up the possible temperature rises and subsequent climatic impacts.

The analysis by the US National Centre for Atmospheric Research (NCAR) found that climate model projections showing a greater rise in global temperature were likely to be more accurate than those showing a smaller rise. This means not only a higher level of warming, but also that the resulting problems – including floods, droughts, sea level rise and fiercer storms and other extreme weather – would be correspondingly more severe and would come sooner than expected.

It was only a matter of time before somebody broke the fragile social and political consensus surrounding geoengineering, and had a first crack at "experiment Earth".

The news that American businessman Russ George has dumped 100 tonnes of iron sulphate into the Pacific Ocean in an attempt to fertilise algal blooms that absorb carbon dioxide, was received with justified indignation and outrage by campaigners and mainstream scientists. But there have been rumblings (and rumours of shadowy trials) for many years, and the idea of being a "geoengineer" was always going to prove tempting for the likes of George (who is blacklisted at several international ports for previous algae-related misdemeanours).

MPs and environmental campaigners on Thursday condemned the appointment of climate sceptic Peter Lilley to the committee that scrutinises the government's energy and climate policies, calling the move "deeply worrying".

The Tory MP, one of only three MPs to vote against the Climate Change Act in 2008, has been appointed to the energy and climate change select committee. It follows a recent cabinet reshuffle that included John Hayes, a vocal critic of wind power in the past, being installed as the new energy minister, and Owen Paterson, an advocate of shale gas who has also spoken out against windfarms, as environment secretary.

Although climate change is expected to lead to slightly more rainfall at the global level, the timing and distribution of that rain is likely to change, increasing the chance of drought in some regions. The details are very difficult to predict, however. This is partly because regional climate impacts are strongly dependent on large-scale atmospheric circulation patterns like the jet stream, which are hard to model in climate simulations. There is some indication from climate modelling that the Mediterranean, Central America and Western Australia regions may experience reduced precipitation, but there is still considerable uncertainty as climate models do not all agree, because local features such as mountains and rainforests can be important, and because of the large range of natural variability.