Britain has led the developed world in combining economic growth with cutting emissions, with the two finally “uncoupling”, according to a major report into the world economy’s reliance on carbon. PwC’s Low Carbon Economy Index found that the UK’s “carbon intensity” – the level of greenhouse gas emissions per dollar of GDP – had fallen by 10.9% last year, the fastest seen by any economy since the report began seven years ago. “The analysis indicates positive signs of ‘uncoupling’ or economies that can grow while reducing or maintaining a the same level, their carbon emissions per unit of GDP”, said Jonathan Grant, PwC’s director of sustainability and climate change. “Breaking the link between emissions and economic growth is essential to avoid the worst impacts of climate change.” However, the report warned that a step-change was needed ahead of a United Nations climate change summit, with the world economy still reducing emissions at too slow a rate to reach global targets. Carbon Pulse also carries the story.

So far, about 150 nations have submitted pledges to the UN promising to curb CO2 emissions, in advance of the Paris climate summit, but analysts say they are not enough. One think-tank, Climate Analytics, estimates promises so far will lead to a global temperature rise of about 2.7C, well over the 2C “safety threshold”, the BBC reports. Elsewhere the Guardian also reports the conclusions of experts the the pledges will fall short of preventing global temperatures rising by more than 2C. A study of COP21 pledges by Climate Action Tracker, an independent scientific group of European climate experts, also indicates that if all pledges are implemented, then global temperatures will rise by 2.7C. At a meeting in Morocco 36 nations, including the US, India, the UK, Germany and Australia, will judge the pledges for themselves.

Zac Goldsmith, the Conservative candidate for mayor of London, has told a rally in Parliament Square that a third runway at Heathrow would come at a “catastrophic price”, the Times reports. A report by the Airport Commission rejected expansion at Gatwick in favour of Heathrow, but Goldsmith described its report as discredited, bogus and hopeless. John McDonnell, the Labour shadow chancellor whose constituency contains Heathrow, and Sadiq Khan, Labour’s candidate for mayor also attended the rally. “Our air is a killer. It makes you sick and it’s illegal. In those circumstances, how can we say yes to a new runway at Heathrow?”, Khan said.

The UN climate negotiations are heading for failure and need a major redesign if they are to succeed, scientists say in new research published in the journal Nature. The pledges that individual countries are offering ahead of the Paris climate summit in December are too entrenched in self interest, and it would be better instead to focus on a common commitment on the global price of carbon. Prof David MacKay, former chief scientific advisor to Britain’s Department of Energy and Climate Change, said: “The science of cooperation predicts that if all you are doing is naming individual contributions – offers that aren’t coupled to each other – then you’ll end up with a relatively poor outcome.” “If you make a treaty that is based on reciprocity, so ‘I will, if you will’ and ‘I won’t, if you won’t’, then you can end up in a very different position,” he explains.

Developers of gas-fired plant that could power 2.2 million homes admit project is behind schedule and yet to secure investors, the Telegraph reports. The Trafford gas plant was due to be built under a government subsidy scheme called the capacity market, designed to ensure Britain has as much electricity as needed, by paying their owners to guarantee they will be available. The £800 million plant was due to start generating in October 2018.

Heads of 11 companies that generate a third of the world’s electricity urged governments on Sunday to agree clear, long-term policies to underpin a shift to lower-carbon energy, as part of the upcoming UN climate agreement. The letter, by companies in the 11-member Global Sustainable Electricity Partnership (GSEP) did not spell out exactly which policies they favoured, saying they could be “carbon pricing or regulation or any other way to incentivise investments, operations and innovations.” Martine Prevost, executive director of GSEP, told Reuters that the companies were concerned by campaigns by some investors, including pension funds, to divest from fossil fuels.

Government cuts to solar-power subsidies are shortsighted and irresponsible, concludes an Observer editorial on the Conservative party’s energy policy. Osborne seems “more at home tickling the tummies of huge, state-owned companies in China and France”, than tending his domestic, private-sector firms, while subsidy cuts cause “havoc” to the UK’s growing army of small and medium-size “green” companies. These cuts look “particularly irresponsible” in the run-up to the UN climate change talks in Paris.

Renewables are taking a growing share of the energy business, according to a new report by the IEA. But it is important to set what is happening in the context of the whole energy market, Butler says. Renewables have, as yet, barely penetrated the transport sector, which remains dominated by oil, and the industrial sector which – particularly in Asia – remains dominated by coal. Meanwhile subsidies and regulations supporting renewables are vulnerable to changes in public policy. The figures on growth cannot hide the fact that renewables are and will remain a small part of total demand, Butler writes, although such growth does alter the competitive dynamics of the market.

UK subsidies for renewable power leave country paying more for less, writes Jonathan Ford in the Financial Times. “Costly” government investment in low-carbon technologies “has added not one megawatt to Britain’s overall capacity”, he says, because the increase in renewables has been accompanied by the decommissioning of many older, often coal-fired, fossil fuel power stations. The move by energy secretary Amber Rudd to end new subsidies for onshore wind and cut them for solar, “does not go far enough”, he says.

A new modelling study investigates how the cooling impact of an abrupt collapse of the Atlantic Meridional Overturning Circulation (AMOC) would compare with the warming influence of manmade climate change. The AMOC is a ocean circulation pattern that brings warm water northwards from the equator and towards the poles, and then brings cool water back again. The results suggest that the Earth would cool instead of warm for a period of 20 years, with global warming continuing thereafter as if the AMOC never collapsed, but with a globally averaged temperature offset of about 0.8C.

The recent decline in Horn of Africa rainfall during the March–May “long rains” season is unprecedented in the last 2000 years, a new study suggests. The researchers used cores of ancient marine sediments from the nearby Gulf of Aden to reconstruct regional temperature and aridity for the past 2,000 years. The region, which includes Somalia, Djibouti and Ethiopia, will receive progressively less rain during the crucial ‘long rains’ as the climate warms, the study says. This contradicts global climate models, which tend to indicate future warming will bring more rain to the region, the researchers say.

A new study shows for the first time how water drained from a subglacial lake found under the Greenland ice sheet. How meltwater drains from the ice sheet can affect how quickly the ice moves towards the ocean, the researchers say, and this process has been observed in Antarctica but not before in Greenland. They also predict that as the Arctic continues to warm, increasing volumes of surface meltwater routed to the ice sheet bed will cause subglacial lake drainage to become more common in the future.