00:00Today, we're looking back in time on climate in the news.
00:03We typically look many years in the future.
00:05Today, we'll focus on a study that looks at the last half a billion years, Brett, from Quantum Magazine.
00:10They looked at a study recently done that pieced together hundreds of thousands of data points about what the temperature has been on Earth over the last half a billion years, which is when animals have lived.
00:22It seems like a long time, and it is in human time scale, but it's actually quite a short time period in geological time scale.
00:28What else did they find when they looked at this huge temperature record?
00:30Well, the Earth has been 36 degrees Fahrenheit, on average, warmer than it is today.
00:37Way back in the past, it got that hot, but it's also gotten pretty chilly, 11 degrees colder than what it is today.
00:43So a big swing in temperature, but again, over millions and millions of years.
00:47And so these are very large time scales. We typically talk about on this show more of like next hundred years, next thousand years.
00:52In this case, we're talking about the previous hundreds of millions of years, so significantly longer time scales.
00:57What causes these temperature swings over this time period?
01:00Well, CO2 is basically the main driver here.
01:03It's always, global temperatures always moved in lockstep with the changes in atmospheric CO2.
01:09So that's the big driver there. Also changes in the sun, but that's predictable.
01:13The CO2 change is not as predictable, especially what's going on today.
01:16And today, the rate at which the CO2 carbon dioxide is increasing is really the concern.
01:22In fact, the rate at which CO2 is increasing is ten times faster than anything that we've seen in history.
01:28So that is a serious concern.
01:31Yeah, absolutely. Three million years ago, that's about the last time we had atmospheric CO2 levels this high.
01:37And temperatures were about three to six degrees Fahrenheit higher than they are today.
01:42And again, we've thrown in all the CO2 in such a short period of time compared to what it was way back in the past.
01:48Yeah, in fact, the last time that we saw or even was close to seeing CO2 levels increase at the rate they are,
01:54and it was still less than today, was back 250 million years ago right before a mass extinction event known as the Permian Mass Extinction.
02:02That preceded the dinosaur age right after that.
02:05So this study also really looked at the vulnerability as well of how humans are to climate change.
02:14And in fact, we are living in a relatively cool part of the entire last half a billion years.
02:19Yeah, we are. No doubt about that.
02:21But it tells you how hot this planet can get.
02:24And with the carbon dioxide levels in the atmosphere already higher than they have been 800,000 years, you have to worry about that.
02:33And again, we don't have any analog to look back and see what happened because the rate of change, as you mentioned, is unprecedented.
02:40So we are really sort of performing an experiment here in real time that we don't have any proxy to look back to.
02:45I guess as we look forward in the future, the Earth system does tend to balance itself out though, right?
02:49Yeah, the Earth is a very good thermostat.
02:51So yes, we could throw all this CO2 into the atmosphere and we are going to warm a lot, no doubt about that.
02:56But eventually, perhaps tens of thousands of years from now, things may start to balance out and we cool down again.
03:02But that doesn't mean though that we as humans or other animals would be adapted to living on such a warm planet.
03:07So that is the serious concern.
03:09For other information about climate, other stories, you can find that at AccuWeather.com slash climate.
03:14Yeah.
03:15We are going to be working on climate.
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