China’s pledge to the UN to cut its emissions intensity by60-65% by 2030 could see the country peak its emissions by 2027 -ahead of its self-imposed 2030 peaking goal – if it hits the topend of this range, analysis by Carbon Brief shows.

As the Airports Commission recommends a third runway atHeathrow, Carbon Brief looks at the climate implications of theexpanding aviation sector in the UK and across theglobe.

China, the world’s largest emitter of greenhouse gases, hasmade its pledge – or “intended nationally determined contribution”- to the UN. In a statement following a meeting of Premier LiKeqiang and Francois Hollande, China said it would reduce itsemissions intensity by 60-65% by 2030 from 2005 levels. It is alsotargeting an increase in the share of non-fossil fuels in itsprimary energy consumption to about 20% by 2030. BBC science editorDavid Shukman said it was a “significant moment” but that it doesnot mean China will stop using fossil fuels any timesoon. The Guardiansays this meansincreasing installed wind capacity to 200GW and solar to around100GW.The New York Timessays thedecision will be closely scrutinised by policymakers “especially inWashington”. Reuterspoints out that China hasnot said the level at which its emissions will peak. China’sannouncement also failed to impress Australian foreign ministerJulie Bishop – The Guardianreports her commentsthat China’s position has been known “for some time”.

A meeting of Barack Obama and Dilma Rousseff has yielded ajoint statement from the US and Brazil over efforts to tackleclimate change. The two countries have pledged to increase theshare of electricity derived from renewables to 20% by 2030. Brazilalso committed to restoring 12m hectares of forest. The Financial Timespoints out thetargets could face obstacles in the US, as it depends on Obama’splan to cut emissions from power plants, which faces legal andpolitical challenges.Reutersreports that, in a pressconference, Rousseff pledged “zero deforestation” by 2030, althoughthe statement itself focuses on stemming only illegaldeforestation. Both The WashingtonPostand The New York Timeshighlight that,combined with the China announcement, yesterday was a significantmoment for climate action.

The US administration has dealt a blow to Shell’s plans todrill in the Arctic. Protections for polar bears and walruses meanthat the company will not be able to drill with two rigs closetogether simultaneously, as it had planned. This will slow thedrilling process. Separately, Reuters reportedthat Shell’s second oildrilling rig has now left the Seattle port for Alaska.The Hillalso has thestory.

South Korea joined China, Serbia and Iceland in submittingits climate pledge to the UN yesterday. Its target is a reductionin greenhouse gas emissions by 37% from business-as-usual levels by2030. According to Reuters, this is higher than its earlierplan for a 15-30% cut. RTCCalso has the story.

A decision by the Supreme Court against an EnvironmentalProtection Agency air pollution rule will not impact Obama’s CleanPower Plan, says Janet McCabe, head of the air pollution office atthe EPA. A rule set to be finalised this summer seeks to curbemissions from existing power plants in the US. The Washington Examinerexamineshow this week’s ruling could affect the EPA’s efforts to clean upthe US power sector.

The Howard Davies Airports Commission has recommended thatthe UK expands its airport capacity by building a third runway atHeathrow. Carbon Briefexplained yesterdaywhy this decision could make it difficult for the UK to tackleclimate change. The mainstream media has yet to cover the climateimplications of the decision, although The Guardianhighlights that theCommission has already ruled out a fourth runway as there is no”sound…environmental case” for it. The recommended third runwayshould also come with conditions on air pollution, itreports.

The UK government has only itself to blame for the rejectionof fracking plans in Lancashire, writes Geoffrey Lean. Theirapproach to shale gas – including the decision to target Balcombeand allowing fracking under people’s homes – has driven greenprotesters to unite with “Middle Britain”, giving both the power tosuccessfully oppose the technology.

The UK has always been able to point to its climate changelegislation to back up its assertion that it is a leader in thefield, but that is no longer enough. The UK is not on track to meetits carbon budgets in the 2020s, and urgent action needs to betaken, write Lord Deben and Lord Krebs, the day after they releasedthe Committee on Climate Change’s progress report for2014. Carbon Briefcovered the contentsof the report.

Using data on water use during hydraulically fracturing atover 260,000 oil and gas wells between 2000 and 2014, researchershave created the first US map of the amount of water used infracking. The researchers found that water use ranges from aslittle as 9,800 litres to as much as 37m litres per well. The studyalso finds that horizontally-drilled wells tend to use more waterthan those vertically or diagonally-drilled.

Researchers have identified an unexpected process thatregulates methane emissions from freshwater wetlands – the largestnatural source of methane. The study finds that high rates ofanaerobic methane oxidation – a process once thought insignificantin these environments – substantially reduce atmospheric emissionsof methane. Without this process, emissions from freshwaterwetlands could be 30 to 50% greater, the study says.

Marine-terminating glaciers control most of Greenland’s icedischarge into the ocean, but undercutting is affecting theirstability and how easily icebergs break off, or ‘calve’, into theocean, new research suggests. The study finds the front of icecliffs go deeper into the ocean than previously measured and theirice faces are neither vertical nor smooth. This allows warm, saltyAtlantic waters to melt the ice at rates of meters per day, thestudy says, creating cavities in the ice.