The world is “way off track” in dealing with the climate emergency and time is fast running out, the UN secretary general has said.

António Guterres sounded the alarm at the launch of the UN’s assessment of the global climate in 2019. The report concludes it was a record-breaking year for heat, and there was rising hunger, displacement and loss of life owing to extreme temperatures and floods around the world.

Scientists said the threat was greater than that from the coronavirus, and world leaders must not be diverted away from climate action.

The climate assessment is led by the UN’s World Meteorological Organization (WMO), with input from the UN’s agencies for environment, food, health, disasters, migration and refugees, as well as scientific centres.

In 2019 the oceans were at the hottest on record, with at least 84% of the seas experiencing one or more marine heatwaves. Surface air temperatures around the world were the hottest ever recorded, after a natural El Niño event boosted figures in 2016.

The report says results from the World Glacier Monitoring Service indicate 2018-19 was the 32nd year in a row in which more ice was lost than gained. The melting of land ice combined with thermal expansion of water pushed sea levels up to the highest mark since records began.

The long-term decline of Arctic sea ice also continued in 2019, with the September average extent – usually the lowest of the year – the third worst on record.

“Climate change is the defining challenge of our time. We are currently way off track to meeting either the 1.5C or 2C targets that the Paris agreement calls for,” said Guterres. 2019 ended with a global average temperature of 1.1C above pre-industrial levels. “Time is fast running out for us to avert the worst impacts of climate disruption and protect our societies.”

He added: “We need more ambition on [emission cuts], adaptation and finance in time for the climate conference, Cop26, in Glasgow, UK, in November. That is the only way to ensure a safer, more prosperous and sustainable future for all people on a healthy planet.”

Prof Brian Hoskins, of Imperial College London, said: “The report is a catalogue of weather in 2019 made more extreme by climate change, and the human misery that went with it. It points to a threat that is greater to our species than any known virus – we must not be diverted from the urgency of tackling it by reducing our greenhouse gas emissions to zero as soon as possible.”

Timeline Half a century of dither and denial – a climate crisis timeline Show The physicist Edward Teller tells the American Petroleum Institute (API) a 10% increase in CO2 will be sufficient to melt the icecap and submerge New York. “I think that this chemical contamination is more serious than most people tend to believe.” Lyndon Johnson’s President’s Science Advisory Committee states that “pollutants have altered on a global scale the carbon dioxide content of the air”, with effects that “could be deleterious from the point of view of human beings”. Summarising the findings, the head of the API warned the industry: “Time is running out.” Shell and BP begin funding scientific research in Britain this decade to examine climate impacts from greenhouse gases. A recently filed lawsuit claims Exxon scientists told management in 1977 there was an “overwhelming” consensus that fossil fuels were responsible for atmospheric carbon dioxide increases. An internal Exxon memo warns “it is distinctly possible” that CO2 emissions from the company’s 50-year plan “will later produce effects which will indeed be catastrophic (at least for a substantial fraction of the Earth’s population)”. The Nasa scientist James Hansen testifies to the US Senate that “the greenhouse effect has been detected, and it is changing our climate now”. In the US presidential campaign, George Bush Sr says: “Those who think we are powerless to do anything about the greenhouse effect forget about the White House effect … As president, I intend to do something about it.” A confidential report prepared for Shell’s environmental conservation committee finds CO2 could raise temperatures by 1C to 2C over the next 40 years with changes that may be “the greatest in recorded history”. It urges rapid action by the energy industry. “By the time the global warming becomes detectable it could be too late to take effective countermeasures to reduce the effects or even stabilise the situation,” it states. Exxon, Shell, BP and other fossil fuel companies establish the Global Climate Coalition (GCC), a lobbying group that challenges the science on global warming and delays action to reduce emissions. Exxon funds two researchers, Dr Fred Seitz and Dr Fred Singer, who dispute the mainstream consensus on climate science. Seitz and Singer were previously paid by the tobacco industry and questioned the hazards of smoking. Singer, who has denied being on the payroll of the tobacco or energy industry, has said his financial relationships do not influence his research. Shell’s public information film Climate of Concern acknowledges there is a “possibility of change faster than at any time since the end of the ice age, change too fast, perhaps, for life to adapt without severe dislocation”. At the Rio Earth summit, countries sign up to the world’s first international agreement to stabilise greenhouse gases and prevent dangerous manmade interference with the climate system. This establishes the UN framework convention on climate change. Bush Sr says: “The US fully intends to be the pre-eminent world leader in protecting the global environment.” Two month’s before the Kyoto climate conference, Mobil (later merged with Exxon) takes out an ad in The New York Times titled Reset the Alarm, which says: “Let’s face it: the science of climate change is too uncertain to mandate a plan of action that could plunge economies into turmoil.” The US refuses to ratify the Kyoto protocol after intense opposition from oil companies and the GCC. The US senator Jim Inhofe, whose main donors are in the oil and gas industry, leads the “Climategate” misinformation attack on scientists on the opening day of the crucial UN climate conference in Copenhagen, which ends in disarray. A study by Richard Heede, published in the journal Climatic Change, reveals 90 companies are responsible for producing two-thirds of the carbon that has entered the atmosphere since the start of the industrial age in the mid-18th century. The API removes a claim on its website that the human contribution to climate change is “uncertain”, after an outcry. Exxon, Chevron and BP each donate at least $500,000 for the inauguration of Donald Trump as president. Mohammed Barkindo, secretary general of Opec, which represents Saudi Arabia, Kuwait, Algeria, Iran and several other oil states, says climate campaigners are the biggest threat to the industry and claims they are misleading the public with unscientific warnings about global warming. Jonathan Watts

The WMO said its report provided authoritative information for policymakers on the need for climate action and showed the impacts of extreme weather.

A heatwave in Europe was made five times more likely by global heating, and the scorching summer led to 20,000 emergency hospital admissions and 1,462 premature deaths in France alone. India and Japan also sweltered and Australia started and ended the year with severe heat and had its driest year on record. Australia had “an exceptionally prolonged and severe fire season”, the WMO noted.

Floods and storms contributed most to displacing people from their homes, particularly Cyclone Idai in Mozambique and its neighbours, Cyclone Fani in south Asia, Hurricane Dorian in the Caribbean, and flooding in Iran, the Philippines and Ethiopia. The number of internal displacements from such disasters is estimated to have been close to 22 million people in 2019, up from 17 million in 2018.

The US saw heavy rains, with the total from July 2018 to June 2019 being the highest on record. Total economic losses in the US for the year were estimated at $20bn, the WMO said.

Unpredictable climate and extreme weather was a factor in 26 of the 33 nations that were hit by food crises in 2019, and was the main driver in 12 of the countries. “After a decade of steady decline, hunger is on the rise again – over 820 million suffered from hunger in 2018, the latest global data available,” the report says.

The WMO said unusually heavy precipitation in late 2019 was also a factor in the severe desert locust outbreak in the Horn of Africa, which is the worst for decades and expected to spread further by June 2020 in a severe threat to food security.

Prof Dave Reay, of the University of Edinburgh, said: “This annual litany of climate change impacts and inadequate global responses makes for a gut-wrenching read. Writ large is the ‘threat multiplier’ effect that is climate change on the biggest challenges faced by humanity and the world’s ecosystems in the 21st century.”