Global Warming Threshold Nears Irreversibility as Human Emissions Reach Critical Level

Rising greenhouse gas emissions are on track to cross a key threshold for limiting global warming by early 2028, according to a new study. By that point, the world will have emitted enough carbon dioxide to create a 50-50 chance or greater that the globe will be locked in to 1.5 degrees Celsius (2.7 degrees Fahrenheit) of long-term warming since preindustrial times. This level of gas accumulation, driven mainly by fossil-fuel burning, is sooner than previously predicted and will have severe consequences, including more frequent and severe heat waves, droughts, and storms.

Key Takeaways:

• The world is producing 46 billion tons of carbon dioxide per year, putting it on track to release 143 billion more tons before the 1.5 degree threshold becomes technically inevitable.
• The 1.5 degree limit is a critical point, beyond which many small island nations could disappear due to sea level rise and climate change impacts become increasingly extreme.
• The rate of human-caused warming per decade has increased to nearly half a degree (0.27 degrees Celsius) per decade.
• Earth's energy imbalance is accelerating, with a 25% increase over the past decade, indicating that the planet is absorbing more heat than it releases.
• Crossing the 1.5 degree threshold means increasingly frequent and severe climate extremes, including unprecedented heat waves, droughts, and storms.
• The 1.5 degree goal is considered aspirational and not realistic, but efforts to curb emissions and mitigate climate change impacts must continue regardless.

Statistics:

• 143 billion: The additional tons of carbon dioxide that must be emitted before the 1.5 degree threshold becomes technically inevitable.
• 46 billion: The number of tons of carbon dioxide emitted per year by the world.
• 1.5 degrees C: The critical temperature limit beyond which climate change impacts become increasingly extreme and small island nations may disappear due to sea level rise.
• 50-50: The chance that the world will be locked in to 1.5 degrees C of long-term warming by 2028 if emissions continue at current rates.
• 25%: The increase in Earth's energy imbalance over the past decade.

Sources:

• "Things aren't just getting worse. They're getting worse faster," by Zeke Hausfather et al., published in the journal by Date.
• The 2015 Paris agreement
• The study "Things aren't just getting worse. They're getting worse faster," by Zeke Hausfather et al. ( exact details not provided)
• The report by Piers Forster et al. published in the journal ( exact details not provided)
• The Associated Press' climate and environmental coverage receives financial support from multiple private foundations (no specific date or details provided)