Human activity has caused at least half of climate change in the last half century, hundreds of scientists say. They are 95% certain of this, the surest they've ever been, says a United Nations report published Friday.
That activity? Driving cars, running power plants on coal and oil, torching swathes of forestland and debris; anything involving burning carbon-based fuels and emitting greenhouse gasses.
The Assessment Report from the Intergovernmental Panel on Climate Change is the benchmark study on global warming published every few years. Nearly 1,000 researchers from around the world work on the document, which then undergoes review by about as many scientists.
The IPCC released a summary report Friday and plans to post the full version, roughly 2,500 pages, online on Monday.
This year's report further strengthens the suspicions scientists have already ascertained.
In 2007, the climate researchers were already 90% sure people were behind a seemingly small rise in global average temperature of about half a degree Celsius (1 degree Fahrenheit) that has already notched up extreme weather events such as heat waves, droughts and flooding.
The effects they are already causing are expected to increase for a century or more, the report reads. Weather catastrophes, previously called storms of the century, are on their way to striking every 20 years or even more frequently.
This means, unfortunately, we could see more EF5 tornadoes like the one that ground up Moore, Oklahoma, stronger and more floods like those that inundated Colorado towns, another Sandy or Katrina or two in our lifetimes, more crops wiped out by drought, larger forests consumed by roaring wildfires.
The Arctic ice cap could melt nearly completely in summer, and sea levels would continue to rise. In the Antarctic, the ice cap could continue to increase slightly.
And if greenhouse gas emissions continue to climb as they have, the resulting temperature rise and its deadly effects would get even worse, the report says.