Scientists have released what can be seen as the most urgent and far-reaching call yet for world governments to cut their greenhouse gas emissions and stop global warming.

They warn of dying corals, melting sea ice and rising sea levels. These effects are inevitable with any level of global warming, but the conclusion of the report is that they will be far worse if the temperature increase is 2C, compared to a more ambitious target of 1.5C.

The report is the result of years of research and then a week of frantic negotiations between scientists and government officials at a meeting in South Korea.

But what exactly does the report say, and what does it mean for the global community?

What is the IPCC report?

Its goal was to gather together all the available scientific literature and produce a report that laid out two future scenarios. One in which the Earth’s average temperature was allowed to increase by 1.5C above pre-industrial temperatures (since around 1850), and one in which it increased by 2C.

The report has taken over two years to produce and included the assessment of more than 6,000 scientific studies.

The point was to create a document that could help those in power with their efforts to ward off climate change and support sustainable economic development while also eradicating poverty.

How did it come about?

The report was commissioned by the United Nations (UN) after the Paris climate agreement in 2015.

At the time, a coalition of rich and poor nations pushed for a commitment to “pursue efforts to limit the temperature increase even further to 1.5C” as well as the “well below” 2C target set by the agreement.

The UN then asked its scientific body the Intergovernmental Panel on Climate Change (IPCC) to get to work finding out what this stretch goal would mean, and how it could be achieved.

10 photographs to show to anyone who doesn't believe in climate change Show all 10 1 /10 10 photographs to show to anyone who doesn't believe in climate change 10 photographs to show to anyone who doesn't believe in climate change A group of emperor penguins face a crack in the sea ice, near McMurdo Station, Antarctica Kira Morris 10 photographs to show to anyone who doesn't believe in climate change Floods destroyed eight bridges and ruined crops such as wheat, maize and peas in the Karimabad valley in northern Pakistan, a mountainous region with many glaciers. In many parts of the world, glaciers have been in retreat, creating dangerously large lakes that can cause devastating flooding when the banks break. Climate change can also increase rainfall in some areas, while bringing drought to others. Hira Ali 10 photographs to show to anyone who doesn't believe in climate change Smoke – filled with the carbon that is driving climate change – drifts across a field in Colombia. Sandra Rondon 10 photographs to show to anyone who doesn't believe in climate change Amid a flood in Islampur, Jamalpur, Bangladesh, a woman on a raft searches for somewhere dry to take shelter. Bangladesh is one of the most vulnerable places in the world to sea level rise, which is expected to make tens of millions of people homeless by 2050. Probal Rashid 10 photographs to show to anyone who doesn't believe in climate change Sindh province in Pakistan has experienced a grim mix of two consequences of climate change. “Because of climate change either we have floods or not enough water to irrigate our crop and feed our animals,” says the photographer. “Picture clearly indicates that the extreme drought makes wide cracks in clay. Crops are very difficult to grow.” Rizwan Dharejo 10 photographs to show to anyone who doesn't believe in climate change Hanna Petursdottir examines a cave inside the Svinafellsjokull glacier in Iceland, which she said had been growing rapidly. Since 2000, the size of glaciers on Iceland has reduced by 12 per cent. Tom Schifanella 10 photographs to show to anyone who doesn't believe in climate change A river once flowed along the depression in the dry earth of this part of Bangladesh, but it has disappeared amid rising temperatures. Abrar Hossain 10 photographs to show to anyone who doesn't believe in climate change A shepherd moves his herd as he looks for green pasture near the village of Sirohi in Rajasthan, northern India. The region has been badly affected by heatwaves and drought, making local people nervous about further predicted increases in temperature. Riddhima Singh Bhati 10 photographs to show to anyone who doesn't believe in climate change A factory in China is shrouded by a haze of air pollution. The World Health Organisation has warned such pollution, much of which is from the fossil fuels that cause climate change, is a “public health emergency”. Leung Ka Wa 10 photographs to show to anyone who doesn't believe in climate change Water levels in reservoirs, like this one in Gers, France, have been getting perilously low in areas across the world affected by drought, forcing authorities to introduce water restrictions. Mahtuf Ikhsan

What were its main conclusions?

Things are not looking good. We are on track to reach 1.5C between 2030 and 2052 if temperatures continues to increase at the current rate, and 3C by the end of the century.

Once we hit 2C warming, the world will be a profoundly different place. There will be almost no coral reefs remaining, the Arctic will be completely devoid of ice during summer at least once a decade, and huge numbers of animals and plants will become extinct as their habitat becomes smaller and smaller.

The impact for humans will be enormous, particularly in areas already vulnerable such as the low-lying coastal regions of Bangladesh and Vietnam, and island territories like Kiribati and the Maldives. Sea level rise will drive millions from their homes, and crop yields will fall dramatically in sub-Saharan Africa, Southeast Asia, and Central and South America.

Is there any reason to be hopeful?

Yes, but it’s going to take serious effort at every level of society. The researchers behind the report used words like “unprecedented” to describe the kind of changes that will need to take place if we are going to stay below the 1.5C target.

IPCC: limiting global warming would require 'unprecedented changes', says Professor Jim Skea

What does this mean for fossil fuels?

Fossil fuel consumption is the main producer of greenhouse gases, so this is the sector that will need to see the biggest changes.

CO2 emissions must be cut by 45 per cent from 2010 levels by 2030 to curb warming at 1.5C. By 2050 we need to be at “net zero”, meaning any remaining CO2 being pumped into the atmosphere needs to be sucked back out somehow.

This will mean planting lots of trees, and also investing in technologies that capture carbon from the air and store it somehow. Most of these technologies are still essentially experimental, meaning relying on them too heavily could be risky.

In most pathways to a 1.5C future, renewable energy sources are expected to supply up to 85 per cent of our electricity needs by 2050. This may ruffle some feathers as even in nations that have committed strongly to tackling climate change, such as the UK and Germany, fossil fuel extraction is still well underway.

Can individual people make a difference?

The authors concluded that “limiting global warming to 1.5C would require rapid, far-reaching and unprecedented changes in all aspects of society”, and this apparently means individuals as well.

Some of these changes will be partly top-down, such as a move away from petrol and diesel cars to electric vehicles. Governments can ease this transition by incentivising people to switch to cleaner vehicles, but there is no doubt that this will be a massive and noticeable change in the next couple of decades if the IPCC warnings are taken seriously.

Other points from the report can be interpreted as affecting people on a more personal level. The move towards “less resource-intensive diets”, for example, will likely entail eating less meat – something not everyone will be pleased to hear.

Has there been any controversy surrounding the report?

Not necessarily the report itself, but the Summary for Policymakers – a 33-page document which was the subject of most media reports – has drawn some criticism. The summary is the result of a week of negotiations with government representatives, while the report is a purely scientific document.

As a result, there have been accusations levelled by some that despite its apocalyptic warnings, the summary has been somewhat watered down to appease governments. There were reports of pushback by Saudi Arabia and the US during the negotiations, for example.

However, broadly speaking the report’s conclusions are clear, and should be suitably dramatic to encourage politicians to take serious action to tackle climate change.

What will happen next?