World of trouble: This is the state of our climate – and it’s a hot mess
Scientists paint a devastating picture of pollution, melting ice and disasters - and we're running out of time fast
Scientists monitoring Earth’s climate and environment have delivered a cascade of grim news this year, adding a sense of urgency to UN talks that started on Sunday in Poland on how best to draw down the greenhouse gases that drive global warming.
The 2015 Paris Agreement calls on humanity to block the rise in Earth’s temperature at “well below” 2°C compared with pre-industrial levels, and 1.5°C if possible.
Here is a summary of recent findings:
Earth’s average surface temperature from January to October 2018 was 1°C higher than the 1850-1900 baseline.
Long-term warming is caused by the accumulation of heat-trapping greenhouse gases in the atmosphere, especially carbon dioxide (CO2) cast off when fossil fuels are burned to produce energy.
Seventeen of the hottest years on record have occurred since the start of the 21st century, with 2018 ranking as the fourth warmest.
405.5 parts per million
The concentration of carbon dioxide (CO2) in the atmosphere reached 405.5 parts per million (ppm) in 2017, the highest in at least three million years and a 45% jump since the pre-industrial era.
The last time CO2 was at that level, oceans were 10m to 20m higher.
Concentrations of the second-most important greenhouse gas, methane (CH4), have also risen sharply owing to leakage from the gas industry’s fracking boom and flatulence from expanding livestock.
After remaining stable for three years, carbon pollution increased more than 1% in 2017 to 53.5 billion tons of CO2-equivalent, a measure that includes all main greenhouse gases. Emissions are on track to climb again in 2018.
At that pace, Earth will pass the 1.5°C mark as early as 2030.
To cap global warming at 2°C, emissions must decline a quarter within a dozen years. To stay under 1.5°C, they will have to drop by more than half.
Arctic summer sea ice shrank in 2018 to a low of 4.59 million km² well above the record low of 3.39 million km² set in 2012.
But long-term trends are unmistakable: Arctic sea ice cover is declining at a rate of more than 13% per decade, relative to the 1981-2010 average.
Climate models predict the Arctic Ocean could, in some years, be ice free as early as 2030.
The World Meteorological Organisation (WMO) says there are clear links between climate change and increases in the intensity and frequency of extreme weather.
The number of climate-related extreme events – such as droughts, wildfires, heatwaves, floods and cyclones – has doubled since 1990, research has shown.
The intensity of typhoons battering China, Taiwan, Japan and the Korean Peninsula since 1980 has increased by 12% to 15%.
Natural disasters drive more than 25 million people into poverty every year, according to the World Bank, and cause annual losses in excess of half a trillion dollars.
Water that expands as it warms and runoff from ice sheets atop Greenland and Antarctica currently add about 3mm to sea levels per year. Since 1993, the global ocean watermark has gone up by more than 85mm.
That pace is likely to pick up, threatening the homes and livelihoods of tens of millions of people in low-lying areas around the world.
Melting glaciers could lift sea levels 1m by 2100, and – with only 2°C of warming – by several metres more over the following centuries.
One-fifth of species affected
Of the 8,688 animal and plant species listed as “threatened” on the International Union for the Conservation of Nature’s (IUCN) Red List, a fifth have been hit by climate change.
From 1970 to 2014, the global population of vertebrates (birds, reptiles, amphibians, mammals and fish) plummeted by about 60%, due mainly to killing for food or profit, and habitat loss.
The number of species is declining 100 to 1,000 times faster than only centuries ago, which means the planet has entered a “mass extinction event” – only the sixth in the past half-billion years.
• Sources: Nasa, NSIDC, UNEP, WMO, IPCC, peer-reviewed studies.