Published September 26, 2017
Human activity is the dominant cause of the rapid rise in climate change, according to a leaked report.
The New York Times obtained a draft of the 2017 U.S. Global Change Research Program's Climate Science Special Report, assembled by federal authorities.
The report states that "it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence."
A finalized version of the report is awaiting approval from President Trump and his administration.
Here are five major takeaways from the report:
1. Global temperatures are rising
The global average temperature increased by more than 1.2 degrees Fahrenheit (0.7 degrees Celsius) in the last 30 years.
The report states that average temperatures have risen faster in the past few decades than at any time in the past 1,700 years. Sixteen of the last 17 years were the warmest years on record.
2. Significant atmospheric changes are inevitable
In the United States alone, the average annual temperature has increased by 1.8 degrees Fahrenheit (1 degree Celsius) since 1901. That number will only increase, according to the report.
More record-setting years will be routine in decades to come. Urban areas will feel the change on a more dramatic scale due to urban heat island effects.
3. Humans are the dominant cause
Human activity is the dominant cause of this warming since the mid-20th century.
The report states that humans have caused 92 to 123 percent of the rise in temperature between 1951-2010.
The authors did evaluate naturally occurring atmospheric phenomena such as El Niño, but found that natural influence was "limited to a small fraction of observed climate trends over decades."
4. Extreme weather events are happening more frequently
Cold waves are dropping in frequency while heat waves are increasingly prevalent, the report states.
Precipitation extremes are also becoming more common. Heavy precipitation events have surged in the U.S. since 1901, most dramatically in the Northeast.
"Recent droughts and associated heat waves have reached record intensity in some regions of the United States," the report said.
More evaluation is needed to scientifically and definitively link climate change to a rise in hurricanes, tornadoes and winter storms.
5. Oceans are rising and heating up
Oceans have been absorbing excess heat from greenhouse gas warming since the mid-20th century, the report states.
Sea levels have risen between 7-8 inches (12-21 cm) since 1900. Roughly 3 of those inches (7 cm) are from 1993 to the present.
Relative sea level rise is predicted to be higher in the northeastern U.S. and the western Gulf of Mexico than the rest of the globe.
Sea level rise will likely "increase the frequency and extent of extreme flooding associated with coastal storms, such as hurricanes and nor'easters," according to the report.