THE evidence for global warming is "unequivocal", and it is "extremely likely" that human activity has been the dominant cause of the phenomenon since the mid-20th century, a new UN report concludes.

The fifth assessment of the Intergovernmental Panel on Climate Change (IPCC) is based on about 9000 peer-reviewed scientific papers, and 50,000 comments from expert reviewers (Comment 27 September).

Published on Friday last week, the summary of the report,Climate Change 2013: The physical science basis,states that: "Warming in the climate system is unequivocal, and since 1950 many changes have been observed throughout the climate system that are unprecedented over decades to millennia."

It is "extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century", the report states. "Extremely likely" refers to a probability of 95 to 100 per cent.

The Professor of Climate and Environmental Physics at the University of Berlin, Dr Thomas Stocker, who co-chairs the working group that produced the report, said: "Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse-gas emissions."

The group has predicted that the earth will warm by more than 1.5°C by the end of the 21st century, relative to 1850-1900, possibly by more than 2°C. Sea levels are ex- pected to rise at a faster rate than that seen in the past 40 years, by between 26 and 81cm. In the Copenhagen Accord in 2009, governments promised to prevent the rise of global temperature by 2°C above pre-industrial levels.

Professor Stocker warned that the effects of climate change would persist "for many centuries", even if emissions were to stop.

The chairman of the Mission and Public Affairs Council, Philip Fletcher, said last Friday that the report made it "clearer than ever that climate change is happening; that we, the human race, are largely or completely responsible for that; and that we really ought to proceed on that basis rather than just hoping that it will all turn out to be wrong."

The Church of England is committed to reducing its carbon footprint by 80 per cent by 2050, with an interim target of 42 per cent by 2020. St Michael and All Angels, in Withington, Gloucester, is believed to be the first zero-carbon church in the UK, since the PCC took measures that included installing a biomass boiler and solar panels (Real Life, 1 October 2010).

Mr Fletcher said: "There are things we do well, and things we do badly, but we have been seeking to work at shrinking our own footprint for some time. We know that we should be doing more. . . We are taking it seriously, and we know we are part of the problem."

On Friday, Christian Aid's senior climate-change adviser, Dr Alison Doig, said: "As a developed, industrialised country, the UK has to lead the way by ending our dependence on fossil fuels, and investing in clean, renewable sources of energy, which we are fortunate enough to be blessed with in the UK."