climate change global warming cyclical chad myers nws orig_00002610.jpg
climate change global warming cyclical chad myers nws orig_00002610.jpg
Now playing
01:19
Climate change is cyclical, but this is worse
Mandatory Credit: Photo by JIM LO SCALZO/EPA-EFE/Shutterstock (11895253o)
An image made with a drone shows fuel tanks at a Colonial Pipeline breakout station in Woodbine, Maryland, USA, 08 May 2021. A cyberattack forced the shutdown of 5,500 miles of Colonial Pipeline's sprawling interstate system, which carries gasoline and jet fuel from Texas to New York.
Cyberattack forces shutdown of Colonial Pipeline in US, Woodbine, USA - 08 May 2021
Jim Lo Scalzo/EPA-EFE/Shutterstock
Mandatory Credit: Photo by JIM LO SCALZO/EPA-EFE/Shutterstock (11895253o) An image made with a drone shows fuel tanks at a Colonial Pipeline breakout station in Woodbine, Maryland, USA, 08 May 2021. A cyberattack forced the shutdown of 5,500 miles of Colonial Pipeline's sprawling interstate system, which carries gasoline and jet fuel from Texas to New York. Cyberattack forces shutdown of Colonial Pipeline in US, Woodbine, USA - 08 May 2021
Now playing
02:12
Pipeline shutdown could push fuel prices higher
ATLANTA - APRIL 30:  A Boeing 757 with a new Delta Airlines logo sits on the tarmac following the company's emergence from bankruptcy at Hartsfield Jackson International Airport April 30,2007 in Atlanta, Georgia. The 757 sports new branding that will appear on more than 900 planes, at airports and on advertising.  (Photo by Barry Williams/Getty Images) 757
Barry Williams/Getty Images North America/Getty Images
ATLANTA - APRIL 30: A Boeing 757 with a new Delta Airlines logo sits on the tarmac following the company's emergence from bankruptcy at Hartsfield Jackson International Airport April 30,2007 in Atlanta, Georgia. The 757 sports new branding that will appear on more than 900 planes, at airports and on advertising. (Photo by Barry Williams/Getty Images) 757
Now playing
01:45
Hear cockpit audio of Delta pilots reporting bird strike
CNN
Now playing
05:21
Palestinians fight eviction from homes in East Jerusalem
CNN
Now playing
01:38
Lawmakers push airlines to drop flight credit restrictions
ORLANDO, FLORIDA - FEBRUARY 28:  Former President Donald Trump addresses the Conservative Political Action Conference held in the Hyatt Regency on February 28, 2021 in Orlando, Florida. Begun in 1974, CPAC brings together conservative organizations, activists, and world leaders to discuss issues important to them. (Photo by Joe Raedle/Getty Images)
Joe Raedle/Getty Images
ORLANDO, FLORIDA - FEBRUARY 28: Former President Donald Trump addresses the Conservative Political Action Conference held in the Hyatt Regency on February 28, 2021 in Orlando, Florida. Begun in 1974, CPAC brings together conservative organizations, activists, and world leaders to discuss issues important to them. (Photo by Joe Raedle/Getty Images)
Now playing
02:15
Trump issues bizarre statement about Kentucky Derby winner
KRDO
Now playing
01:26
Six killed in shooting at Colorado birthday party
Justin Bamberg nr intv 05092021
CNN
Justin Bamberg nr intv 05092021
Now playing
04:05
Hear why this lawmaker is comparing his state to North Korea
Now playing
03:29
Renowned chef offers $50 gift card to those who get vaccinated
Kevin McCarthy 05092021
Fox News
Kevin McCarthy 05092021
Now playing
03:30
Watch McCarthy confirm support for Stefanik for GOP leadership post
LOUISVILLE, KENTUCKY - MAY 01: Medina Spirit #8, ridden by jockey John Velazquez, (R) crosses the finish line to win the 147th running of the Kentucky Derby ahead of Mandaloun #7, ridden by Florent Geroux, and Hot Rod Charlie #9 ridden by Flavien Prat , and Essential Quality #14, ridden by Luis Saez, at Churchill Downs on May 01, 2021 in Louisville, Kentucky. (Photo by Tim Nwachukwu/Getty Images)
Tim Nwachukwu/Getty Images
LOUISVILLE, KENTUCKY - MAY 01: Medina Spirit #8, ridden by jockey John Velazquez, (R) crosses the finish line to win the 147th running of the Kentucky Derby ahead of Mandaloun #7, ridden by Florent Geroux, and Hot Rod Charlie #9 ridden by Flavien Prat , and Essential Quality #14, ridden by Luis Saez, at Churchill Downs on May 01, 2021 in Louisville, Kentucky. (Photo by Tim Nwachukwu/Getty Images)
Now playing
02:50
Kentucky Derby winner's trainer speaks out after doping allegations
CNN
Now playing
02:02
WH Covid-19 response coordinator: We're turning the corner on pandemic
caitlyn jenner immigration path to citizenship bash intv sot vpx_00000000.png
caitlyn jenner immigration path to citizenship bash intv sot vpx_00000000.png
Now playing
01:20
Caitlyn Jenner: Immigrants should have a legal path to citizenship
CNN/@walidbarahmeh
Now playing
03:04
China's out-of-control rocket lands on Earth
CNN Weather
Now playing
01:53
Severe storms threaten millions this Mother's Day
CNN
Now playing
03:05
3 injured in Times Square shooting
Getty Images
Now playing
00:46
Actress Tawny Kitaen dies at 59
(CNN) —  

The most catastrophic wipe-out on Earth didn’t happen to the dinosaurs.

A new study found extreme changes in the atmosphere killed almost 100% of life on Earth about 2 billion years ago.

Researchers sampled barite, a mineral more than 2 billion years old, in subarctic Canada’s Belcher Islands. Rocks that old “lock in chemical signatures,” helpful clues for researchers to uncover what the atmosphere was like when the rocks first formed, co-lead author and Stanford University Ph.D. candidate Malcolm Hodgskiss told CNN.

There is such thing as too much oxygen

The study focused on a phenomenon called the “Great Oxidation Event.” It goes like this: Billions of years ago, only micro-organisms survived on Earth. When they photosynthesized, they altered the chemical composition of the atmosphere, creating a glut of oxygen they ultimately could not sustain.

Micro-organisms exhausted the nutrients they needed to create oxygen, which knocked the Earth’s atmosphere off-kilter. This led to an “enormous drop” in the biosphere – the amount of life on Earth. Scientists weren’t sure just how drastic the drop was until now.

The team’s calculations showed that anywhere from 80 to 99.5% of organisms were wiped out at the end of the Great Oxidation Event, Hodgskiss said. There were simply too many of them, and they produced too much oxygen.

“Even our most conservative estimates would exceed estimates for the amount of life that died off during the extinction of the dinosaurs approximately 65 million years ago,” he said.

Ancient revelations that are relevant today

How did researchers study what the world was like before humans ever lived in it? They combined a model of how much carbon dioxide and oxygen there might’ve been in the atmosphere then based on past research with their chemical measurements from the barite to calculate how much life there was then.

The findings are older than most life on Earth, but they’re relevant to the planet today because Earth is still vulnerable to atmospheric changes, Hodgskiss said. Oceans are heating up, which affects how numerous some nutrients are. Runoff in oceans disrupts underwater ecosystems, too, threatening photosynthesizing organisms that contribute more than half of the oxygen in the Earth’s atmosphere.