Last Year Was Earth’s Warmest Year On Record Since 1880

Space.com

2023 has set the record for 'Earth’s warmest year since 1880,' according to NASA's Goddard Space Flight Center. Learn more about why that matters here.   Credit; NASA's Goddard Space Flight Center

Transcript

00:002023 was the hottest year on record by a large margin. But why does NASA, a space agency,

00:10even look at Earth's temperature record?

00:27Let's start from the beginning. NASA's Goddard Institute for Space Studies, or GIS, creates

00:34its global temperature record using land and ocean surface data collected from thousands

00:38of instruments and buoys around the world. But this critical dataset of Earth's temperature

00:43has an origin story that starts 100 million miles away, on planet Venus.

00:51It's 900 degrees hot at the surface, has powerful high altitude winds, and is blanketed by a

00:57dense carbon dioxide atmosphere.

00:59The Goddard Institute for Space Studies here in New York was set up in the early 1960s

01:04to provide a connection between NASA and the academic community. And so it was very much

01:10an ideas shop, and so we spent a lot of time with, you know, the formation of galaxies

01:15and black holes and planetary program and Voyager. And we were involved very early on

01:21in some of the missions to Venus and Jupiter.

01:25Back then, when GIS researchers were studying the weather on Venus, scientists noticed something

01:29fascinating. A thick atmosphere made up of clouds and carbon dioxide was trapping heat.

01:35So much heat that Venus had a surface hot enough to melt lead. This trapping of heat

01:40is known as the greenhouse gas effect. One of the lead Venus researchers at GIS, Dr.

01:45James Hansen, realized that greenhouse gases were also building up in Earth's atmosphere.

01:51So he switched his sights to his home planet and pledged to model the changing atmosphere

01:55of Earth. And to verify or ground truth his model, he needed real-world measurements

01:59over time. So he began keeping track of Earth's global temperature record, dating back to

02:051880, when there was a sufficient amount of data to pull from.

02:09We used our expertise in understanding literally the clouds of Venus and the clouds and dynamics

02:18of Jupiter, and then we took that and we started to think about how you would do the same thing

02:24for the Earth. Since then, GIS has kept its sights on the

02:27global temperature record. And that was the birth of GIS as a climate

02:33modeling institution. And scientists have seen a clear trend in

02:37that record, rising temperatures. And they know why.

02:42The key difference between, say, this decade and the decade before and the decade before

02:47that is that the temperatures have been rising because of our activities, because of principally

02:54the burning of fossil fuels. Without the presence of humans, Earth's temperature

03:03would rise and fall due to a complex array of natural drivers.

03:07With human presence, however, the temperature just continues to rise.

03:11We know that by observing temperature anomalies. Measuring temperature anomalies means that

03:17we look at the change over time rather than absolute temperatures.

03:22The data map you see here isn't showing that the Arctic saw warmer temperatures than the

03:26tropics. It's saying the Arctic was that much warmer

03:29than the Arctic has been in previous years, which is an anomaly in Arctic temperatures.

03:35But how do we get those anomaly measurements?

03:37Let's say you want to track if apples these days are generally larger, smaller, or the

03:44same size as they were 20 years ago. In other words, you want to track the change

03:49over time. Imagine each person on your apple measuring

03:52team has their own food scale. Person A measures apple 1, and their food

03:57scale reads 6 ounces. Person B measures the same apple, but their

04:01scale reads 7 ounces. Since these scales are calibrated differently,

04:06your team ended up with two different recorded weights for the same exact apple.

04:11There's some imprecision in the measurements. And to account for that, when you compare

04:14this apple's measurement to the apples growing next year, you'll need to look at their difference

04:18rather than absolute weights, focusing on the anomaly, or how much heavier or lighter

04:23the next apple is from year to year. So for temperatures, while it would be great

04:29to have the same exact scale or thermometer all over the world measuring the temperature

04:33in the same exact way, we don't. Instead, we focus on how much warmer or colder the

04:38temperatures are in each place based on their own instruments.

04:43Another factor to consider is since you're tracking apples from all over the globe, there

04:47are differences in baseline weights. Let's say apples grown in Florida are generally

04:51larger than apples grown in Alaska. Like in real life, how Floridian temperatures

04:56are generally much higher than Alaskan temperatures. So how do you track the change in apple sizes

05:01from apples grown all over the world while still accounting for their different baseline

05:05weights? By focusing on the difference within each area rather than the absolute weights.

05:12So when it comes to the temperature record, scientists aren't comparing temperatures

05:16in Bermuda to temperatures in Greenland and averaging them together for net warming. Instead,

05:21we're comparing the change in temperatures in Bermuda to the change in temperatures in

05:26Greenland. Again, we look at the anomaly measurements to track the change over time. Now let's scale

05:32this example up.

05:33If you have a weather station, let's say here in New York City, and you compare it

05:38to a weather station in Washington DC or Montreal, they tell very different stories about the

05:44absolute temperature, right? So Montreal is colder and Washington DC is often warmer.

05:50But when they move up and down, when there's a month that is warmer or colder, it's basically

05:55the same in all three locations. And so by looking at the anomalies, how much warmer

06:00it is than normal for that particular point, and then you look at those anomalies at all

06:06those different points and you can average those, it turns out that you can fill out

06:11the gaps much more effectively.

06:15As you can see, this big picture global temperature is comprised of much smaller concentrated

06:21data points from all over the world. So while globally temperatures averaged out to be record

06:26hot, it wasn't record hot in every single location around the world. But why did 2023

06:32see record heat? Well, to put it simply, a combination of high greenhouse gas emissions

06:38and the transition out of three consecutive years of La Nina conditions and into El Nino

06:43conditions led to record breaking heat. But the year was in some respects still surprisingly

06:48hot and NASA is continuing its research on why. Typically, the largest cause of short

06:55term year to year differences in temperature is usually La Nina and El Nino weather patterns.

07:00La Nina generally cools things down while El Nino warms them up. The largest cause of

07:05long term decade by decade differences in temperature is greenhouse gas emissions and

07:10the subsequent trapped heat by greenhouse gases. So while we don't expect every year

07:15to be a new record like 2023, we do expect new records as long as we continue to increase

07:21greenhouse gas emissions. The key thing to take away from all of this is that the long

07:29term trends are pretty much relentlessly up. We're going to continue to have records be

07:37broken because that baseline is moving all the time. And then the weather is sitting

07:43on top of that. And so when the weather is warmer than normal, then we're going to get

07:48these records. But even when it's cooler than normal, we don't go back to what it was.

07:58Hopefully we've answered some of your questions surrounding 2023's noteworthy temperature

08:02record. But you might be left wondering what we're doing about it. NASA is your space agency

08:08when it comes to powering solutions. We're helping other agencies and groups with efforts

08:13to reduce future warming. Clean solar and wind power is being planned using modeling

08:18from NASA Goddard's Mara and NASA Langley's Power. NASA is also developing green aviation

08:25that aims to make air travel more sustainable through new flight technology. And we're also

08:30helping people adapt to climate change challenges that are already here through programs like

08:35Open ET, helping water management across the Western U.S. And Black Marble, which uses

08:41nightlight data to provide critical information to first responders after hurricanes and other

08:46hazards and disasters.

Category

Transcript

Recommended