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
Credit; NASA's Goddard Space Flight Center
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00:00 [MUSIC]
00:03 >> 2023 was the hottest year on record by a large margin.
00:07 But why does NASA, a space agency, even look at Earth's temperature record?
00:11 [MUSIC]
00:21 Let's start from the beginning.
00:28 [MUSIC]
00:30 NASA's Goddard Institute for Space Studies, or GIS, creates its global temperature
00:35 record using land and ocean surface data collected from thousands of instruments
00:39 and buoys around the world.
00:41 But this critical data set of Earth's temperature has an origin story that
00:45 starts 100 million miles away, on planet Venus.
00:47 [MUSIC]
00:50 >> It's 900 degrees hot at the surface, has powerful high altitude winds, and
00:56 is blanketed by a dense carbon dioxide atmosphere.
00:59 >> The Goddard Institute for Space Studies here in New York was set up in the early
01:03 1960s to provide a connection between NASA and the academic community.
01:08 And so it was very much an ideas shop, and so we spent a lot of time with
01:14 the formation of galaxies and black holes and planetary program and Voyager.
01:19 And we were involved very early on in some of the missions to Venus and Jupiter.
01:25 >> Back then, when GIS researchers were studying the weather on Venus,
01:28 scientists noticed something fascinating.
01:31 A thick atmosphere made up of clouds and carbon dioxide was trapping heat.
01:35 So much heat that Venus had a surface hot enough to melt lead.
01:39 This trapping of heat is known as the greenhouse gas effect.
01:43 One of the lead Venus researchers at GIS, Dr.
01:45 James Hansen, realized that greenhouse gases were also building up an Earth's
01:49 atmosphere.
01:51 So he switched his sights to his home planet and
01:53 pledged to model the changing atmosphere of Earth.
01:56 And to verify or ground truth his model,
01:58 he needed real world measurements over time.
02:01 So he began keeping track of Earth's global temperature record,
02:04 dating back to 1880, when there was a sufficient amount of data to pull from.
02:08 >> We used our expertise in understanding literally the clouds of Venus and
02:16 the clouds and dynamics of Jupiter.
02:19 And then we took that and we started to think about how you would do the same
02:23 thing for the Earth.
02:25 >> Since then, GIS has kept its sights on the global temperature record.
02:29 >> And that was the birth of GIS as a climate modeling institution.
02:35 >> And scientists have seen a clear trend in that record, rising temperatures.
02:39 And they know why.
02:40 >> The key difference between, say, this decade and the decade before and
02:46 the decade before that is that the temperatures have been rising because
02:51 of our activities, because of principally the burning of fossil fuels.
02:56 [MUSIC]
03:00 >> Without the presence of humans, Earth's temperature would rise and
03:04 fall due to a complex array of natural drivers.
03:07 With human presence, however, the temperature just continues to rise.
03:11 We know that by observing temperature anomalies.
03:15 Measuring temperature anomalies means that we look at the change over time
03:19 rather than absolute temperatures.
03:21 The data map you see here isn't showing that the Arctic saw warmer temperatures
03:26 than the tropics.
03:27 It's saying the Arctic was that much warmer than the Arctic has been
03:31 in previous years, which is an anomaly in Arctic temperatures.
03:35 But how do we get those anomaly measurements?
03:37 [MUSIC]
03:40 Let's say you wanna track if apples these days are generally larger, smaller, or
03:44 the same size as they were 20 years ago.
03:47 In other words, you want to track the change over time.
03:49 Imagine each person on your apple measuring team has their own food scale.
03:55 Person A measures apple one, and their food scale reads six ounces.
03:59 Person B measures the same apple, but their scale reads seven ounces.
04:04 Since these scales are calibrated differently,
04:06 your team ended up with two different recorded weights for the same exact apple.
04:11 There's some imprecision in the measurements.
04:13 And to account for that when you compare this apple's measurement to the apples
04:16 growing next year, you'll need to look at their difference rather than absolute
04:19 weights, focusing on the anomaly or
04:22 how much heavier or lighter the next apple is from year to year.
04:25 So for temperatures, while it would be great to have the same exact scale or
04:30 thermometer all over the world measuring the temperature in the same exact way,
04:35 we don't.
04:36 Instead, we focus on how much warmer or
04:38 colder the temperatures are in each place based on their own instruments.
04:43 Another factor to consider is since you're tracking apples from all over
04:46 the globe, there are differences in baseline weights.
04:49 Let's say apples grown in Florida are generally larger than apples grown in
04:52 Alaska, like in real life how Floridian temperatures are generally much higher
04:57 than Alaskan temperatures.
04:59 So how do you track the change in apple sizes from apples grown all over
05:02 the world while still accounting for their different baseline weights?
05:06 By focusing on the difference within each area rather than the absolute weights.
05:11 So when it comes to the temperature record,
05:14 scientists aren't comparing temperatures in Bermuda to temperatures in Greenland,
05:18 and averaging them together for net warming.
05:21 Instead, they're comparing the change in temperatures in Bermuda
05:24 to the change in temperatures in Greenland.
05:27 Again, we look at the anomaly measurements to track the change over time.
05:31 Now, let's scale this example up.
05:33 >> If you have a weather station that's say here in New York City and
05:38 you compare it to a weather station in Washington DC or Montreal,
05:42 they tell very different stories about the absolute temperature, right?
05:45 So Montreal is colder, Washington DC is often warmer.
05:50 But when they move up and down, when there's a month that is warmer or
05:54 colder, it's basically the same in all three locations.
05:57 And so by looking at the anomalies,
05:59 how much warmer it is than normal for that particular point.
06:04 And then you look at those anomalies at all those different points, and
06:07 you can average those.
06:08 It turns out that you can fill out the gaps much more effectively.
06:13 >> As you can see, this big picture global temperature is comprised of much
06:19 smaller concentrated data points from all over the world.
06:23 So while globally temperatures averaged out to be record hot,
06:26 it wasn't record hot in every single location around the world.
06:29 But why did 2023 see record heat?
06:34 Well, to put it simply, a combination of high greenhouse gas emissions and
06:39 the transition out of three consecutive years of La Nina conditions and
06:42 into El Nino conditions led to record breaking heat.
06:46 But the year was, in some respects, still surprisingly hot.
06:49 And NASA is continuing its research on why.
06:52 Typically, the largest cause of short term year to year differences in
06:56 temperature is usually La Nina and El Nino weather patterns.
07:00 La Nina generally cools things down while El Nino warms them up.
07:04 The largest cause of long term decade by decade differences in temperature
07:08 is greenhouse gas emissions and the subsequent trapped heat by greenhouse gases.
07:13 So while we don't expect every year to be a new record like 2023,
07:17 we do expect new records as long as we continue to increase greenhouse gas
07:22 emissions.
07:22 >> The key thing to take away from all of this is that
07:28 the long term trends are pretty much relentlessly up.
07:34 We're going to continue to have records be broken
07:39 because that baseline is moving all the time.
07:42 And then the weather is sitting on top of that.
07:44 And so when the weather is warmer than normal,
07:47 then we're gonna get these records.
07:49 But even when it's cooler than normal, we don't go back to what it was.
07:52 [BLANK_AUDIO]
07:58 >> Hopefully we've answered some of your questions surrounding 2023's noteworthy
08:02 temperature record.
08:03 But you might be left wondering what we're doing about it.
08:06 NASA is your space agency when it comes to powering solutions.
08:11 We're helping other agencies and groups with efforts to reduce future warming.
08:15 Clean solar and wind power is being planned using modeling from NASA Goddard's
08:20 Mera and NASA Langley's Power.
08:23 NASA is also developing green aviation that aims to make air travel more
08:27 sustainable through new flight technology.
08:30 And we're also helping people adapt to climate change challenges that are already
08:33 here through programs like Open ET, helping water management across the Western US.
08:39 And Black Marble, which uses nightlight data to provide critical information to
08:43 first responders after hurricanes and other hazards and disasters.
08:47 [MUSIC]
08:55 [BLANK_AUDIO]