Sea levels rise. Devastating storms, heat waves and droughts become more common. Those are among the things that will likely happen if the average global temperature rises more than 2 degrees celsius (3.6 degrees Fahrenheit) above pre-industrial levels because of climate change.
A new study in the journal Nature Climate Change published this week says keeping that increase below 2 degrees is a long shot. Rather, it says there's a 90 percent chance that the Earth will warm beyond that threshold by the end of the century.
And that's even if countries implement policies to curb greenhouse gas emissions.
"It seems like the 2 C target is going to be very hard to achieve," said Adrian Raftery, professor of statistics and sociology at the University of Washington and lead author of the study. "So, we may be looking at trying to limit the amount over 2 C."
He said if humans continue to burn fossil fuels at currents rates, the average global temperature could rise more than 5 degrees celsius by the end of the century.
But as temperatures increase, what will happen to Southern California?
Southern California is going to get hotter
"Everywhere will get hotter, but there will be some difference in terms of which areas get hotter than others," said Daniel Walton, who's with the Institute of Environment and Sustainability at UCLA.
Southern California is made up of a lot of different micro-climates. So areas near the coast are protected by their proximity to the ocean, Walton said, while inland areas like the San Fernando Valley will see warmer conditions as heat gets trapped in the bowl-like valley.
"The ocean generally is expected to warm less than inland areas," Walton said. "So, places like Santa Monica will have warming that's lower than, say, Riverside or Palm Springs."
Walton crunched the average temperatures for August in areas including Santa Monica, Woodland Hills, downtown L.A., Pasadena, San Bernardino and Palm Springs. First he looked at what those temperatures were in 2010. Then he calculated what things could feel like by 2100, assuming that current emissions patterns continue.
If the world takes a concerted effort to curb greenhouse gases, Walton said, temperatures wouldn't rise as much.
Walton's estimates end at 2100, but he said temperatures will likely continue to rise above those levels — but it's unclear how much.
Sea levels will rise
Another likely change: rising sea levels.
The California Ocean Science Trust says sea levels in the state are already rising twice as fast as they did in the 1990s. By 2100, ocean levels in Southern California could rise as much as 3.6 feet if the average global temperature increases more than 2 degrees celsius. If countries manage to keep the temperature rise below that point, local sea levels would still likely rise 2.5.
Rising sea levels will lead to more coastal flooding during storms and increased erosion, according to a 2017 report from the California Ocean Science Trust.
Wildfires will become more common and pollution could get worse
Wildfires will likely become more common through the end of the century, with the fire season possibly extending from October to November, according to a 2014 study published in Climate Dynamics. Increased temperatures dry out vegetation, turning it into perfect fuel for fires. And when it does burn, fine particulate matter that can get trapped in lungs is pumped into the atmosphere.
Emissions from cars and trucks, which already account for the majority of the air pollution in Southern California, could also become more of a health problem as temperatures heat up.
"As climate changes and the planet gets warmer, that drives the chemical reactions that create pollutants like ozone and fine particulate matter in the atmosphere," Jason West, a researcher at the University of North Carolina at Chapel Hill, said.
In turn, increased levels of ozone and fine particulate matter from wildfires and burning fossil fuels will have detrimental effects on people's health.
"Those pollutants cause people to die early, because of heart attack, stroke, lung cancer [and] chronic obstructive pulmonary disease," West said.
What can Southern Californians do?
Southern Californians can do a lot about pollution, but not much about overall global temperatures.
Since the majority of the air pollution in Southern California comes from cars and trucks, zero-emissions vehicles would likely make a difference.
Los Angeles is also trying to tackle the so-called "heat island effect," which is when paved areas absorb solar heat and radiate it back out. It can raise surrounding temperatures by as much as 19 degrees. The city's answer: painting over sections of asphalt with white reflective paint and requiring more roofs to have reflective coatings.
The bottom line: We’re on track to a hotter Earth. The question is how hot humanity is going to allow the planet, including our small piece of it, to get.