The world is “way off track” in dealing with the climate emergency and time is fast running out, António Guterres, the UN secretary general has said.
The UN’s assessment of the global climate in 2019 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.
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.”
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
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.
“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.”
Even large ecosystems the size of the Amazon rainforest can collapse in a few decades, according to a study. The research reveals that once a tipping point has been passed, breakdowns do not occur gradually like an unravelling thread, but rapidly like a stack of Jenga bricks after a keystone piece has been dislodged.
The authors looked at 42 previous cases of “regime shift”. This is the term used to describe a change from one state to another – for example, the collapse of fisheries in Newfoundland, the death of vegetation in the Sahel, desertification of agricultural lands in Niger, bleaching of coral reefs in Jamaica, and the eutrophication (too much nutrients which induce excessive growth of algae which result in oxygen depletion of the water) of Lake Erhai in China.
Based on their statistical analysis, the authors estimate an ecosystem the size of the Amazon (approximately 5.5m km2) could collapse in approximately 50 years once a tipping point had been reached. "The larger the system, the greater the fragility and the proportionately quicker collapses,” John Dearing, professor in physical geography at the University of Southampton and lead author of the study, said.
The paper concludes: “We must prepare for regime shifts in any natural system to occur over the ‘human’ timescales of years and decades, rather than multigenerational timescales of centuries and millennia. Humanity now needs to prepare for changes in ecosystems that are faster than we previously envisaged through our traditional linear view of the world, including across Earth’s largest and most iconic ecosystems, and the social-ecological systems that they support.”
A separate study last week warned the Amazon could shift within the next decade into a source of carbon emissions rather than a sink, because of damage caused by loggers, farmers and global heating.
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