In September 2015 he overwhelmingly won the Labour leadership contest and was appointed party leader.
Support for a ban on fracking
In July 2019 the Labour Party released analysis showing that fracking, if it goes ahead in Britain, would stop the country reaching a net zero target for carbon emissions by 2050.
- “We need urgent action to tackle the climate emergency, and that means the prime minister immediately banning fracking once and for all.
- “Instead of bending the knee to a few corporations who profit from extracting fossil fuels from the ground, we need to change course now. It’s the next generation and the world’s poorest who will pay the price if this Conservative government continues to put the interests of a few polluters ahead of people.” 
Corbyn told campaigners that:
- “I want to see a green industrial revolution in Britain. I want to see sustainability. We cannot go on with this level of CO2 emissions and global warming, otherwise we are all damaged if not doomed.
- A green industrial revolution will create around 400,000 jobs, high-skilled, good quality, well-paid jobs, all around the country. That is a future for our children. We have a short window, as a people, to reduce CO2 emissions, to prevent global warming beyond 1.5C, in order to protect the planet.
- “I want to say well done everyone in Lancashire that opposed fracking here, as in Derbyshire and other places, in Sussex, and the way in which you have made sure the issue is kept alive.”
Corbyn also commented that Johnson's current short-term focus on climate and fracking and his close ties with US president Donald Trump were a disaster risk for the planet. “...unless there is a real intervention by government on fracking, on measurements of emissions on aircraft and shipping … then we are deluding ourselves that we are actually adhering to climate change targets.
- “Since he [Johnson] has no plans to do anything to protect it and is closely aligned with Donald Trump who claims that the Paris climate change accords are a danger to the American economy and that is a kind of signal to other industrial economies … well your short-term economic interests come ahead of the longer-term environmental issues.” 
In response, the fracking industry resorted to its oft-cited argument of the need for Britain to develop homegrown gas and stop relying on gas imports, including from places such as Qatar and Russia. Cuadrilla’s chief executive, Francis Egan said:
- “I am very disappointed that Labour appear to favour continued and increasing levels of gas imports by ship from the Middle East, Africa or the United States or by pipeline from Russia rather than developing a well-regulated job creating UK shale gas industry.
UKOOG, the trade lobby group for the UK onshore oil and gas industry, released a press statement saying Labour 'can't have it both ways - we either offshore our emissions or back UK industry'
- "We will still need natural gas in 2050. It's better that we source it from home, creating fewer emissions and more UK jobs and investment, than rely on the likes of Qatar, Russia and the US to meet our demand." 
Labour leadership contest 2015
- Simon Fletcher, campaign director. Fletcher has worked a number of key Labour figures including; Ken Livingstone for twelve years, including eight years as his chief of staff when he was Mayor of London; Tony Benn and is believed to have been a member of Socialist Action; and Ed Miliband, as his trade union liaison officer. He will work for Corbyn out of the Transport Salaried Staffs' Association Union offices in London.
- Kat Fletcher, agent. Was elected president of the National Union of Students in 2004, after running on an anti-tuition fees ticket and defeating the Labour Students candidate. Fletcher then worked at the Centre for Excellence in Leadership, as Ed Miliband's head of volunteers in his Labour leadership campaign in 2010 and as Corbyn's agent in the 2015 general election. She has been a councillor since 2013 and is currently deputy mayor on Islington council and runs small London pub company Handmade Pubs.
- Jon Trickett, adviser. MP for Hemsworth since 1996 and the current Labour Party deputy chairman, Tricket was one of the first MPs to back Corbyn. As an MP Trickett has worked as a PPS to Peter Mandelson and was a key ally of Ed Miliband, serving as his shadow minister without a portfolio and worked with him on speeches and policy announcements.
- Harry Fletcher, volunteer. Was assistant general secretary of trade union NAPO for over twenty years until 2013. Founder of Digital Trust, a not-for-profit group aiming to tackle digital abuse.
- Len McCluskey. The general secretary of Unite, Britain's biggest trade union and Labour's biggest donor.
- Janet Chapman
- Katy Clark
- Neale Coleman - Policy director, Labour Party
- Stephanie Driver - Head of events, Labour Party *
- Andrew Fisher - Political adviser
- Kat Fletcher - Researcher
- Simon Fletcher - Chief of staff
- Billie Heath
- Joss MacDonald - Diary and correspondence administrator, overseas visit to Israel and West Bank 11-15 November, funded by Fateh UK
- Anneliese Midgley
- Seamus Milne
- James Murray - Housing policy adviser, Executive member of London Borough of Islington
- Nicolette Petersen
- Nancy Platts
- Jack Reardon Bond
- Gavin Sibthorpe - Events officer/researcher
- Joshua Simons
- Kevin Slocombe - Media and spokesperson services for Labour Party
- William Smith - Political assistant | Niall Sookoo | Ayse Vali - Diary manager
- Angie Williams - Office administrator 
- Jeremy Corbyn, www.parliament.uk, 29 October 2013.
- Mikey Smith, Jeremy Corbyn demands Boris Johnson stop 'bending the knee' and ban fracking, The Mirror, 29 July 2019, accessed 30 July 2019
- Nazia Parveen, Johnson and Trump's close ties risk disaster for planet, The Guardian, 30 July 2019, accessed same day
- 'Labour can't have it both ways - we either offshore our emissions or back UK industry, UKOOG press release, 30 July 2019, accessed same day.
- BBC News Labour leadership: Jeremy Corbyn enters race, 3 June 2015, accessed 27 July 2015.
- Emily Gosden Jeremy Corbyn's team: the key figures backing the left-winger's leadership bid Telegraph, 26 July 2015, accessed 27 July 2015.
- Register of interests of members' secretaries and research assistants, 23 March 2016, parliament.uk, accessed 19 April 2016