The report issued a stark warning that the window to limit world temperatures to under 1.5°C and avoid the worst climate change impacts could close within the next 12 years.
Its ultimate conclusion was the world must reach global net zero emissions by 2050 to limit average temperatures rising above 1.5°C, an aspiration of the 2015 Paris Agreement.
Policy-makers and climate change advocates have been giving their reaction to the report.
Miguel Arias Cañete & Carlos Moedas, European Commission
"Today's report is a remarkable endeavour of scientists to inform policy-makers worldwide and society at large.
"[The] Special Report confirms that limiting climate change to 1.5°C is necessary to avoid the worst impacts and reduce the likelihood of extreme weather events.
"It demonstrates that human-induced global warming has already reached 1°C above preindustrial levels and is increasing at approximately 0.2°C per decade.
"The impacts of global warming are already transforming our environment and trend changes have been detected in the frequency and intensity of extreme weather events.
The EU will work to address those challenges and expects others to follow. All parties must step up efforts from the pledges made under the Paris Agreement.
"The report shows that 1.5°C is doable, provided we act now and use every tool at our disposal.
"The world will need to raise the collective ambition, we need to deliver on our goals, and we need to start preparing to achieve a carbon neutral economy as soon as possible this century.
"In short, as there is no planet B, saving our planet Earth should be our number one mission.
Al Gore, former US vice president
"Today the world’s leading scientific experts collectively reinforced what Mother Nature has made clear — that we need to undergo an urgent and rapid transformation to a global clean energy economy.
"The Paris Agreement was monumental, but we must now go further, ratchet up commitments and develop solutions that meet the scale of the climate crisis.
"The report will encourage the development of new technologies, which is important.
"However, time is running out, so we must capitalise and build upon the solutions available today. Solving the climate crisis requires vision and leadership.
"Unfortunately, the Trump administration has become a rogue outlier in its shortsighted attempt to prop up the dirty fossil fuel industries of the past.
"The administration is in direct conflict with American businesses, states, cities, and citizens leading the transformation."
Adnan Z. Amin, director-general of the International Renewable Energy Agency (IRENA)
"The IPCC report sends a clear signal and calls for a large-scale transformation of the global energy system.
"A decarbonised energy system, increasingly fueled by renewable sources, is vital to the global response to the threat of climate change.
"IRENA’s analysis shows that renewable energy and energy efficiency represent the most cost-effective pathway for achieving 90% of the energy-related CO2 emission reductions needed to meet the ‘well below 2 degrees objective’ of the Paris Agreement.
"The world of energy is witnessing rapid and disruptive changes. Renewables already account for around a quarter of global electricity generation.
"In the last six years, renewable power capacity additions outpaced additions from fossil fuels and nuclear power combined. However, if we are to meet our climate goals, renewables deployment must accelerate six times faster than today."
Christiana Figueres, former UN climate lead
"There is nothing opaque about this new data.
"The illustrations of mounting impacts, the fast-approaching and irreversible tipping points are visceral versions of a future that no policy-maker could wish to usher in or be responsible for.
"Emissions reductions today are much more important than emissions reductions tomorrow.
"The sooner we bend the curve of global emissions, the more options we will have on the table for safely reaching the necessary, desirable and achievable carbon neutrality by 2050."
source: the Guardian, pic: Chatham House
Giles Dickson, CEO at WindEurope
"The signal the IPCC is giving is clear. We now need to see this converted into action. The EU needs to agree on a ‘zero net carbon’ target for 2050.
"One of the ways of doing this is to go for an ambitious electrification strategy.
"Europe has done quite well at getting renewables into electricity but much less well at getting them into industrial processes, buildings and transport.
"We’ve got to change that if we’re serious about decarbonisation.
"The renewables-based electrification of Europe’s industrial processes, buildings and transport would allow Europe to reduce energy-related CO2 emissions by 90% by 2050. The level of electrification of energy would rise from 24% today to 62% in 2050.
"Doing so is both realistic and affordable. And will help us avoid the worst effects of climate change."
Lars Christian Lilleholt, Danish energy minister
"[The report] stresses the need for the development of radical green technologies and the changes in our way of life here on earth will be imperative to reduce climate change.
"The government is committed to push the international community to climate ambitions in the air — a 3°C increase should not happen.
"We need everyone to take a common responsibility that we have reduced the now very visible consequences of climate change have around the globe.
"We are pushing the EU and our international cooperation, and we are going to press on at COP 24 in Poland in December, so the entire UN take joint responsibility, "
Svenja Schulze, German federal Environment Minister
"We must not lose any more time on climate protection.
"The next few years are crucial, so that our planet does not get out of balance.
"Every tonne of CO 2 avoided, every tenth of a degree of global warming avoided counts, and this transformation brings with it many changes and a great opportunity to make our economy more sustainable and make our society more liveable. "
François de Rugy, French energy minister
"The sad conclusions of the report of the IPCC are a call to action addressed to the world.
"In France, the government has set an ambitious target to achieve carbon neutrality by 2050. But we need more than ever to continue our efforts.
"At the end of the month, we will present our new low carbon strategy. Deployment of clean mobility, phasing out of fossil fuels, [decrease] our energy consumption and our waste production. We must not weaken now.
"We will vigorously mobilize our neighbours to raise the COP21 commitments upwards, and thus lead the rest of the world to meet the objectives of the Paris Agreement."
Claire Perry, UK clean growth minister
"This report should act as a rallying cry for governments around the world to innovate, invest, and raise ambition to avert catastrophic climate change.
"The UK has already shown carbon abatement and prosperity can go hand in hand and we lead the world in clean growth- slashing emissions by more than 40% since 1990 while growing our economy ahead of the G7.
"There is now no excuse and real action is needed."
Chris Stark, chief executive at the UK's Committee on Climate Change
"Already it's clear... that the window to keep global temperatires below the 1.5°C threshold is narrowing rapidly.
"We now look forward to a formal request from UK ministers to begin our assessment of the appropriate statutory framework for climate change in the UK in light of the UK's obligations under the Paris Agreement."
Mike Hughes, president of UK & Ireland at Schneider Electric
"Today’s IPCC report shows that we are guilty of greatly underestimating the challenges associated with global warming and we need to fundamentally change the way we live, if we are to meet climate goals.
"Recognising that people are unlikely to change behaviours on their own places a greater emphasis on technology to help increase energy efficiency and reduce consumption and governments to create a framework that encourages and rewards change.
"Both businesses and government should be doing everything they can to encourage the adoption of more efficient products and practices.
"Efficiency holds the key to our wellbeing and, as a matter of urgency, we must become more aware of our behaviour before the situation is irreversible.
"This includes how we produce goods in manufacturing plants, how we occupy buildings, store our data and our choice of light sources in our businesses and homes.
"Collectively, we must become three times more efficient if we are to successfully power our futures in a sustainable manner."
Nick Molho, executive director, Aldersgate Group
The report presented "compelling environmental, economic and social benefits" to limiting the increase in global temperatures to 1.5°C.
He added: "Major economies now need to increase their existing emissions reduction pledges under the Paris Agreement and adopt net zero emissions targets in line with the conclusions of the IPCC report."
UK National Infrastructure Commission
"Today’s report highlights the devastating impact that rising global temperatures could have on our planet and the need for urgent action to prevent the worst from happening.
"Our National Infrastructure Assessment highlights the need to act now to protect communities from extremes of weather, including floods and droughts.
"It also shows how falling renewables prices and improved technologies mean sources like wind and solar could make up as much as 50 per cent of our energy mix by 2030, and the need for a truly national charging network to help drivers switch from petrol and diesel to electric vehicles.
"These recommendations have been put to Government and we look forward to hearing how they plan to put them into practice."