Complete Transcript

Complete Transcript

Narration:

Transcript:

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2023 was the hottest year on

record by a large margin. But

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why does NASA, a space agency,

even look at Earth's temperature

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record?

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Let's start from the beginning.

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NASA's Goddard Institute for

Space Studies or GISS, creates

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its global temperature record

using land and ocean surface

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data collected from thousands of

instruments and buoys around the

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world. But this critical data

set of Earth's temperature has

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an origin story that starts 100

million miles away-on planet

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Venus.

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It's 900 degrees hot at the sur

face as powerful high altitude

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winds and is blanketed by a

dense carbon dioxide... The

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Goddard Institute for Space

Studies here in New York was set

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up in the early 1960s to provide

a connection between NASA and

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the academic community. And so

it was very much an ideas shop.

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And so we spent a lot of time

with, you know, the formation of

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galaxies and black holes and

planetary program and Voyager

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and we were involved very early

on in some of the missions to

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Venus and Jupiter. Back then,

when GISS researchers were

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studying the weather on Venus,

scientists notice something

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fascinating: A thick atmosphere

made up of clouds and carbon

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dioxide was trapping heat. So

much heat that Venus had a

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surface hot enough to melt lead.

This trapping of heat is known

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as the Greenhouse Gas Effect.

One of the lead Venus

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researchers at GISS, Dr. James

Hansen, realized that greenhouse

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gases were also building up in

Earth's atmosphere. So he

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switched his sights to his home

planet, and pledged to model the

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changing atmosphere of Earth.

And to verify or groundtruth his

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model, he needed real world

measurements over time. So he

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began keeping track of Earth's

global temperature record,

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dating back to 1880, when there

was a sufficient amount of data

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to pull from.

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We used our expertise in

understanding literally the

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clouds of Venus, and the clouds

and dynamics of Jupiter. And

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then we took that, and we

started to think about how you

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would do the same thing for the

Earth. Since then, GISS has kept

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its sights on the global

temperature record. And that was

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the birth of, of GISS as a

climate modeling institution.

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And scientists have seen a clear

trend in that record: rising

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temperatures, and they know why.

The key difference between, say

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this decade and the decade

before and the decade before,

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that is that the temperatures

have been rising because of our

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activities because of

principally the burning of

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fossil fuel.

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Without the presence of humans,

Earth's temperature would rise

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and fall due to a complex array

of natural drivers. With human

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presence, however, the

temperature just continues to

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rise. We know that by observing

temperature anomalies, measuring

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temperature anomalies means that

we look at the change over time

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rather than absolute

temperatures.

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Let's say you want to track if

apples these days are generally

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larger, smaller or the same size

as they were 20 years ago. In

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other words, you want to track

the change over time. Imagine

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each person on your

Apple-measuring team has their

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own food scale. Person A

measures Apple 1 and their food

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scale read 6 ounces. Person B

measures the same apple but

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their scale read 7 ounces. Since

these scales are calibrated

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differently, your team ended up

with two different recorded

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weights for the same exact

apple. There's some imprecision

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in the measurements. And to

account for that when you

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compare this apple's measurement

to the apples growing next year,

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you'll need to look at their

difference rather than absolute

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weights. Focusing on the

anomaly, or how much heavier or

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lighter the next apple is from

year to year.

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So for temperatures, while it

would be great to have the same

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exact scale or thermometer all

over the world measuring the

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temperature in the same exact

way, we don't. Instead we focus

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on how much warmer or colder the

temperatures are in each place

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based on their own instruments.

Another factor to consider is

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since you're tracking apples

from all over the globe there

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are differences in baseline

weights. Let's say apples grown

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in Florida are generally larger

than apples grown in Alaska.

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Like in real life how Floridian

temperatures are generally much

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higher than Alaskan

temperatures. So how do you

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track the

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change in apple sizes from

apples grown all over the world,

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while still accounting for their

different baseline weights? By

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focusing on the difference

within each area, rather than

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the absolute weights. So when it

comes to the temperature record,

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scientists aren't comparing

temperatures in Bermuda to

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temperatures in Greenland, and

averaging them together for net

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warming. Instead, they're

comparing the change in

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temperatures in Bermuda, to the

change in temperatures in

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Greenland. Again, we look at the

anomaly measurements to track

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the change over time. Now, let's

scale this example up.

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If you have a weather station,

that's, say, here in New York

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City, and you compare it to a

weather station in Washington,

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DC, or Montreal, they tell very

different stories about the

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absolute temperature, right? So

Montreal is colder and

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Washington DC is often warmer.

But when they move up and down,

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when there's a month that is

warmer or colder, it's basically

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the same in all three locations.

And so by looking at the

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anomalies, how much warmer it is

than normal for that particular

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point, and then you look at

those anomalies at all those

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different points, and you can

average those, it turns out that

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you can fill out the gaps much

more effectively.

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As you can see, this big

picture, global temperature is

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comprised of much smaller,

concentrated data points from

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all over the world. So while

globally, temperatures averaged

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out to be record hot, it wasn't

record hot in every single

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location around the world.

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But why did 2023 See record

heat? Well, to put it simply a

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combination of high greenhouse

gas emissions, and the

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transition out of three

consecutive years of La Nina

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conditions and into El Nino

conditions led to record

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breaking heat. But the year was

in some respects, still

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surprisingly hot. And NASA is

continuing its research on why.

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Typically, the largest cause of

short term year to year

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differences in temperature is

usually La NIna and El Nino

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weather patterns. La Nina

generally cools things down

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while El Nino warms them up. The

largest cause of long term

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decade by decade differences in

temperature is greenhouse gas

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emissions and the subsequent

trapped heat by greenhouse

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gases. So while we don't expect

every year to be a new record,

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like 2023, we do expect new

records as long as we continue

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to increase greenhouse gas

emissions.

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The key thing to take away from

all of this is that the long

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term trends are pretty much

relentlessly up. We're going to

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continue to have records be

broken, because that baseline is

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moving all the time. And then

the weather is sitting on top of

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that. And so when the weather is

warmer than normal, then we're

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going to get these records. But

But even when it's cooler than

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normal, we don't go back to what

it was.

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Hopefully, we've answered some

of your questions surrounding

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2023's noteworthy temperature

record. But you might be left

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wondering what we're doing about

it. NASA is your space agency

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when it comes to powering

solutions. We're helping other

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agencies and groups with efforts

to reduce future warming. Clean

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solar and wind power is being

planned using modeling from NASA

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Goddard's MERRA, and NASA

Langley's POWER. NASA is also

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developing green aviation that

aims to make air travel more

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sustainable through new flight

technology. And we're also

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helping people adapt to climate

change challenges that are

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already here, through programs

like Open ET helping water

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management across the western US

and Black Marble, which uses

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nightlight data to provide

critical information to first

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responders after hurricanes and

other hazards and disasters.