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The Earth is

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the most

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important planet that we study,

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at least in my opinion.

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And the work that we do from space

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is incredibly valuable

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in giving that this global vantage point,

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the ability to see everything,

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It's like going to the world,

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you know, the top of a big hill

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and you get to look down

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and see everything,

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but there's no place we can do that.

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What we're actually

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on the surface of the earth.

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And so the work that NASA does

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in exploring space

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and finding new ways

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to get instruments

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that look back at Earth

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have given us this

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incredibly rich dataset

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that help us understand

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the world

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and how it's changing over

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the course of multiple decades now

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you know, when NASA's first started

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sending people up into space,

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they would look down at the Earth

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and they would see things

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that we see from the ground.

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But this whole different

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perspective, right?

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They could see the movement

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of these big clouds and weather systems.

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They could see lights at night. Right.

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And so over time,

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that guided

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the development of instruments

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that we've sent into space

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that look back at our planet,

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that are able to monitor

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weather systems,

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that are able to monitor human activity.

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So now those data sets have provided

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this foundation of understand

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how the Earth functions as a planet

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over the course of the

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past several decades.

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Studying the Earth as a

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system is incredibly important

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because the more we look

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at individual variables

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like rainfall or air

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pollutants or temperature,

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we realize how interconnected

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the Earth is as a planet, as a system,

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right when we warm the planet,

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when we increase temperatures,

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we don't just get warmth

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and balmy days, right?

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We get changes in weather systems.

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We get changes

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in the acuteness of pollution episodes

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that send people to the hospital.

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We change the frequency

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and the patterns of wildfires

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so understanding

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all those different variables

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and how connected they are,

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that's one of the most special things

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that we get

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from this record of Earth observations

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and this really impressive

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global perspective

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that NASA's satellites give us

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as Earth scientists

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It's incredibly important for us to study

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how the planet's changing.

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Our observations helped us understand

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how the planet functions.

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But we also know we want to know

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how that's going to evolve

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in coming decades, coming centuries.

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So really understanding the climate

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that we have today

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and how that's changing, that's

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providing this really important

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benchmark to understand

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how extremes might be changing

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and also to understand how the efforts

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that we're all taking to mitigate

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climate change

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are having a positive effect

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both now and in the future.

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So atmospheric chemistry is a

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lot like the chemistry

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that you probably learned

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about in high school.

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But when we talk about

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atmospheric chemistry,

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we're talking about the way

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that that molecules in the form of gases

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react with each other

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to form new molecules,

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many of them

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in very small concentrations.

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But those can be incredibly important

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and affecting things like air quality

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pollution and public health

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and the evolution of climate change

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setting.

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Atmospheric chemistry

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is really, really important for us

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in order to be able to understand

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and predict

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things like air pollution

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episodes, the concentrations

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of greenhouse gases,

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the rates at which

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some of these reactions

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occur are driven by the concentrations

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of different gases in the atmosphere.

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But they can also be affected

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by things like changes in humidity,

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changes in temperature.

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So when we study atmospheric chemistry,

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we're not just looking at

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how are those processes occurring now,

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but how are those going to change

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with climate change.

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How sensitive

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are some of those types of reactions

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to a world that's getting warmer and in

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a lot of cases more moist?

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So greenhouse gases are this

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really important type of gas

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that's present in the atmosphere

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in really, really small concentrations.

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But it's important

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because they're very,

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very efficient

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at trapping

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long wave heat

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that's emitted from the Earth's surface.

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And they can do this

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because greenhouse gases

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are comprised of more than two atoms.

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That means structurally

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they have a little bit

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more ability to move

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and they can absorb that energy

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through rotational

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translational vibrational motion.

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So some of the most important

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greenhouse gases

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that are influenced by

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human activities are carbon

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dioxide or CO2,

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as you may have heard of, called methane,

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nitrous oxide or N2O

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and also water vapor.

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Now, water vapor obviously occurs

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naturally in the atmosphere.

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That's important for

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for sustaining life

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sustaining precipitation.

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But as the planet warms,

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the concentration of water

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vapor can increase.

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So you have this positive feedback,

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as scientists call it, where water vapor

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is contributing to climate change,

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even though it's there

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naturally in the atmosphere.

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So methane is really powerful.

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Greenhouse gas

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is actually more powerful

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on a molecule by molecule

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basis than carbon dioxide,

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even though it's

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present in the atmosphere

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in much smaller concentrations.

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Now, methane is emitted

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by a number of both human

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and natural sources.

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So things like oil

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and natural gas production, landfills,

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wastewater treatment facilities, it's

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also emitted by natural sources

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like wetlands.

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About 30% of the budget is wetlands.

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By many estimates,

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that's really important

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because in some cases, it's harder

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for us to manage and control

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those diffuse natural sources.

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And another reason

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scientists are really concerned

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about what's happening

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with methane right now

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is that methane emissions from places

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like wetlands are temperature sensitive,

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meaning they can accelerate

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in a warming world.

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And we want to make sure we understand

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how wetlands are changing,

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how those human and natural components to

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methane emissions are changing as climate

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change progresses.

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So another reason that methane

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is really important right now

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is that

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policymakers are targeting

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methane emissions as a

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as a major effort to reduce

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emissions from methane in the near term.

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They hope that that buys us some time

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to bring down carbon

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dioxide concentrations in the future.

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So things like trying to reduce

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fugitive emissions from oil,

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natural gas is getting a lot of attention

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because the hope is that

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that can give us some time, both

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because methane is a very powerful gas

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and because there's a lot of agreement

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from both policymakers, industry

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and the general public

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that we have places

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to reduce those emissions

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that'll make life a little bit safer

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and help us reduce

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climate change at the same time.

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So greenhouse gases are really effective

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at trapping heat.

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We know that.

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And most of the warming

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is due to CO2 or carbon dioxide,

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which is built up in the atmosphere

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over the past hundred 50 years.

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And so that's the main driver

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trapping heat

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in the Earth's system

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and causing a lot of the changes

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we associate with climate change.

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So the 1880s is important

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in terms of general dates.

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The technology

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to measure temperature pressure, rainfall

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was being distributed

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in communicated more broadly.

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And so that's one of those

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early dates in history

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where scientists were able to gather

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enough information

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to have a reliable picture

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of global temperature

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in a global sense

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to understand how things are changing.

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So trace

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gases are really important

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in raising global temperatures.

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Most of the atmosphere

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is into and out to atoms,

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and they don't have a lot of flexibility

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to absorb energy. Right.

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But when you have these

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special greenhouse gases

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that have at least three atoms,

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they have more capacity

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to absorb energy and absorb

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that in the molecular bonds

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between those atoms.

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That means that

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even though they're present

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in the atmosphere,

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only in very,

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very small concentrations,

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they have this outsized impact

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on the temperature budget

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in being able

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to very efficiently

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trap energy that's emitted

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back to space from the Earth's surface.

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So the way that heat is

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expressed throughout the planet

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when it's trapped by

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these greenhouse gases

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is is really diverse. Right,

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We see all of these different impacts

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for example,

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we see changes in ocean temperatures

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that can affect ocean biology.

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It also affects ocean currents,

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the presence of ice

297
00:09:42,832 --> 00:09:45,167
at the high and low latitudes.

298
00:09:45,167 --> 00:09:46,961
But we also see changes on land.

299
00:09:46,961 --> 00:09:48,588
We see changes in ecosystems,

300
00:09:48,588 --> 00:09:49,547
changes in growing

301
00:09:49,547 --> 00:09:51,757
season, changes in the frequency

302
00:09:51,757 --> 00:09:53,092
and severity of droughts

303
00:09:53,092 --> 00:09:56,053
that can affect the risk of fires.

304
00:09:56,053 --> 00:09:57,597
We see changes in life.

305
00:09:57,597 --> 00:09:59,432
We see changes in the migration

306
00:09:59,432 --> 00:10:01,892
patterns of birds and fish.

307
00:10:01,892 --> 00:10:03,019
And so these are some of the ways

308
00:10:03,019 --> 00:10:05,021
that the planet is interconnected.

309
00:10:05,021 --> 00:10:06,397
And when we trap heat,

310
00:10:06,397 --> 00:10:07,648
that's not just

311
00:10:07,648 --> 00:10:08,774
expressing itself

312
00:10:08,774 --> 00:10:09,734
as this change

313
00:10:09,734 --> 00:10:11,777
in the daily temperature value,

314
00:10:11,777 --> 00:10:13,362
it's expressing itself

315
00:10:13,362 --> 00:10:15,281
in all of these fundamental ways

316
00:10:15,281 --> 00:10:15,823
that our lives

317
00:10:15,823 --> 00:10:17,950
are influenced day after day.

318
00:10:25,541 --> 00:10:26,125
This is something

319
00:10:26,125 --> 00:10:27,293
people ask a lot, right?

320
00:10:27,293 --> 00:10:27,793
And early

321
00:10:27,793 --> 00:10:29,170
on, people use to focus on

322
00:10:29,170 --> 00:10:30,880
global warming, global warming.

323
00:10:30,880 --> 00:10:32,048
And I think as scientists,

324
00:10:32,048 --> 00:10:34,508
we say climate change more frequently

325
00:10:34,508 --> 00:10:35,843
because global warming

326
00:10:35,843 --> 00:10:36,677
is really only talking

327
00:10:36,677 --> 00:10:38,054
about one part of the problem,

328
00:10:38,054 --> 00:10:39,972
the fact that greenhouse gases trap heat,

329
00:10:39,972 --> 00:10:40,640
and that's expressed

330
00:10:40,640 --> 00:10:42,683
in global temperature increases.

331
00:10:42,683 --> 00:10:43,851
When we talk about climate change,

332
00:10:43,851 --> 00:10:46,062
we're talking about these really complex

333
00:10:46,062 --> 00:10:47,438
interactive effects, things

334
00:10:47,438 --> 00:10:49,440
like changes in vegetation

335
00:10:49,440 --> 00:10:51,233
changes and fires, changes in air

336
00:10:51,233 --> 00:10:53,319
pollution, ocean circulation,

337
00:10:53,319 --> 00:10:55,196
really something as fundamental

338
00:10:55,196 --> 00:10:57,073
as temperature can't change in a vacuum

339
00:10:57,073 --> 00:10:57,948
without affecting

340
00:10:57,948 --> 00:10:59,533
literally every aspect

341
00:10:59,533 --> 00:11:01,160
of the earth as a planet.

342
00:11:01,160 --> 00:11:02,536
And so that's why we like to call it

343
00:11:02,536 --> 00:11:03,329
climate change,

344
00:11:03,329 --> 00:11:04,121
to just make sure

345
00:11:04,121 --> 00:11:05,081
we're encompassing

346
00:11:05,081 --> 00:11:06,415
the full range of effects

347
00:11:06,415 --> 00:11:08,459
that are happening across the planet.

348
00:11:15,675 --> 00:11:18,469
So scientists, policymakers and citizens

349
00:11:18,469 --> 00:11:18,886
all across

350
00:11:18,886 --> 00:11:19,512
the world are working

351
00:11:19,512 --> 00:11:20,012
really hard

352
00:11:20,012 --> 00:11:22,014
to get us to net zero emissions,

353
00:11:22,014 --> 00:11:23,683
to bring us down to a point where

354
00:11:23,683 --> 00:11:25,893
we're not emitting a net amount of carbon

355
00:11:25,893 --> 00:11:26,435
that that

356
00:11:26,435 --> 00:11:30,022
the emissions are balanced by by natural

357
00:11:30,106 --> 00:11:31,732
and imposed things. Right.

358
00:11:31,732 --> 00:11:32,108
But one thing

359
00:11:32,108 --> 00:11:32,775
that's really important

360
00:11:32,775 --> 00:11:34,151
for people to know is, one, it's

361
00:11:34,151 --> 00:11:35,444
going to take us some time to get there.

362
00:11:35,444 --> 00:11:36,779
That's not going to happen overnight.

363
00:11:36,779 --> 00:11:37,905
It's going to happen

364
00:11:37,905 --> 00:11:39,490
over the course of decades.

365
00:11:39,490 --> 00:11:42,159
And even when we get to net zero,

366
00:11:42,159 --> 00:11:43,119
that doesn't mean

367
00:11:43,119 --> 00:11:44,078
that carbon dioxide

368
00:11:44,078 --> 00:11:45,538
concentrations, greenhouse

369
00:11:45,538 --> 00:11:46,872
gas concentrations

370
00:11:46,872 --> 00:11:47,373
fall back

371
00:11:47,373 --> 00:11:49,333
to pre-industrial levels overnight.

372
00:11:49,333 --> 00:11:51,127
We've been emitting these things

373
00:11:51,127 --> 00:11:53,254
for well over a hundred years.

374
00:11:53,254 --> 00:11:55,214
We've been perturbing these cycles

375
00:11:55,214 --> 00:11:56,424
and it's going to take time.

376
00:11:56,424 --> 00:11:59,468
We expect over the course of decades

377
00:11:59,719 --> 00:12:01,095
to even over a century,

378
00:12:01,095 --> 00:12:04,098
to see those decreases in greenhouse

379
00:12:04,098 --> 00:12:05,558
gas concentrations

380
00:12:05,558 --> 00:12:08,936
continue as carbon is absorbed

381
00:12:09,019 --> 00:12:10,479
into natural reservoirs.

382
00:12:10,479 --> 00:12:12,440
And you see more of that balance return.

383
00:12:12,440 --> 00:12:13,315
So that's one thing

384
00:12:13,315 --> 00:12:14,900
that is important for people to note.

385
00:12:14,900 --> 00:12:16,694
Net zero doesn't mean an immediate

386
00:12:16,694 --> 00:12:18,946
end to global climate change.

387
00:12:25,870 --> 00:12:27,705
So scientists look at a

388
00:12:27,705 --> 00:12:29,081
range of explanations for everything.

389
00:12:29,081 --> 00:12:30,166
It's important for people to think

390
00:12:30,166 --> 00:12:31,917
we don't just jump to conclusions.

391
00:12:31,917 --> 00:12:33,919
So we look at all of these explanations

392
00:12:33,919 --> 00:12:34,545
to understand

393
00:12:34,545 --> 00:12:36,380
what are the drivers of climate change,

394
00:12:36,380 --> 00:12:37,214
things like changes

395
00:12:37,214 --> 00:12:38,257
in the solar radiation

396
00:12:38,257 --> 00:12:40,509
cycles, volcanoes that

397
00:12:40,509 --> 00:12:42,011
that erupt and change

398
00:12:42,011 --> 00:12:43,929
atmospheric composition naturally.

399
00:12:43,929 --> 00:12:46,056
And when we do computer simulations,

400
00:12:46,056 --> 00:12:47,725
none of these things can explain

401
00:12:47,725 --> 00:12:49,059
the dramatic changes

402
00:12:49,059 --> 00:12:50,686
that we're seeing in global temperature,

403
00:12:50,686 --> 00:12:52,062
which occur at the same time

404
00:12:52,062 --> 00:12:53,439
as greenhouse gases.

405
00:12:53,439 --> 00:12:55,232
Really only the system makes sense

406
00:12:55,232 --> 00:12:56,025
with the warming

407
00:12:56,025 --> 00:12:56,984
that we know happens

408
00:12:56,984 --> 00:12:59,361
as a result of greenhouse gases.

409
00:12:59,361 --> 00:13:01,697
In addition, people should know that

410
00:13:01,697 --> 00:13:04,658
the imprint of climate change from humans

411
00:13:04,867 --> 00:13:07,369
has a really distinct signature

412
00:13:07,369 --> 00:13:09,121
in terms of temperature.

413
00:13:09,121 --> 00:13:10,456
When you have this warming

414
00:13:10,456 --> 00:13:12,625
for greenhouse gases that traps heat

415
00:13:12,625 --> 00:13:13,918
throughout the atmosphere,

416
00:13:13,918 --> 00:13:14,835
it acts as a blanket

417
00:13:14,835 --> 00:13:16,045
that warms the surface,

418
00:13:16,045 --> 00:13:17,671
but it makes the top of the atmosphere

419
00:13:17,671 --> 00:13:18,923
a little bit colder.

420
00:13:18,923 --> 00:13:20,049
And we can actually see

421
00:13:20,049 --> 00:13:21,592
in the records of observations

422
00:13:21,592 --> 00:13:22,635
that we have

423
00:13:22,635 --> 00:13:24,136
that this fingerprint, this unique

424
00:13:24,136 --> 00:13:25,137
trapping of heat

425
00:13:25,137 --> 00:13:26,472
from greenhouse gases

426
00:13:26,472 --> 00:13:27,848
is occurring at the same time

427
00:13:27,848 --> 00:13:29,099
temperatures are warming.

428
00:13:29,099 --> 00:13:30,726
So that's a really dead giveaway

429
00:13:30,726 --> 00:13:32,478
that this isn't some natural cycle.

430
00:13:32,478 --> 00:13:33,771
This is warming

431
00:13:33,771 --> 00:13:35,022
that's caused by absorption

432
00:13:35,022 --> 00:13:37,274
from greenhouse gases.

433
00:13:43,989 --> 00:13:45,157
So we talk about models.

434
00:13:45,157 --> 00:13:46,242
You probably hear about this a lot.

435
00:13:46,242 --> 00:13:48,911
Models are really just a set of equations

436
00:13:48,911 --> 00:13:49,995
that describe

437
00:13:49,995 --> 00:13:51,539
our best understanding

438
00:13:51,539 --> 00:13:53,707
of the way some system functions.

439
00:13:53,707 --> 00:13:55,125
It can be a lot of equations.

440
00:13:55,125 --> 00:13:57,127
They can be very long and complicated.

441
00:13:57,127 --> 00:13:58,754
They can be solved by supercomputers

442
00:13:58,754 --> 00:13:59,338
and on a grid,

443
00:13:59,338 --> 00:14:00,589
which is actually how

444
00:14:00,589 --> 00:14:02,341
weather and climate models work.

445
00:14:02,341 --> 00:14:03,342
But at the end of the day,

446
00:14:03,342 --> 00:14:04,885
they're really just our best

447
00:14:04,885 --> 00:14:06,428
understanding, encapsulated

448
00:14:06,428 --> 00:14:07,972
in a mathematical form

449
00:14:07,972 --> 00:14:09,056
that help us

450
00:14:09,056 --> 00:14:11,851
integrate and predict into the future.

451
00:14:18,941 --> 00:14:20,276
So the weather and climate models

452
00:14:20,276 --> 00:14:21,026
that we use

453
00:14:21,026 --> 00:14:22,987
to study things like climate change

454
00:14:22,987 --> 00:14:25,197
are made up of these sets of equations.

455
00:14:25,197 --> 00:14:27,867
They're being solved on supercomputers.

456
00:14:27,867 --> 00:14:28,325
But one thing

457
00:14:28,325 --> 00:14:29,326
that's really important to know

458
00:14:29,326 --> 00:14:30,578
is that we don't just make up

459
00:14:30,578 --> 00:14:31,579
these equations, right?

460
00:14:31,579 --> 00:14:32,830
We develop equations

461
00:14:32,830 --> 00:14:34,540
and we refined them over time

462
00:14:34,540 --> 00:14:36,250
using a combination

463
00:14:36,250 --> 00:14:39,003
of satellite data, of ground based data.

464
00:14:39,003 --> 00:14:41,046
So that helps us make and test

465
00:14:41,046 --> 00:14:43,507
the best equations over time.

466
00:14:43,507 --> 00:14:45,050
We're also continually

467
00:14:45,050 --> 00:14:46,427
evaluating those models

468
00:14:46,427 --> 00:14:48,137
with a combination of data to ensure

469
00:14:48,137 --> 00:14:49,847
we know what they do well,

470
00:14:49,847 --> 00:14:52,182
where they can use improvement.

471
00:14:52,182 --> 00:14:55,603
We also use data sets to initialize

472
00:14:55,603 --> 00:14:56,645
predictions, right?

473
00:14:56,645 --> 00:14:58,397
So when we make a weather forecast

474
00:14:58,397 --> 00:14:59,648
that's actually taking data

475
00:14:59,648 --> 00:15:00,482
from satellites,

476
00:15:00,482 --> 00:15:00,900
from ground

477
00:15:00,900 --> 00:15:01,483
based networks,

478
00:15:01,483 --> 00:15:02,735
even from from airplanes,

479
00:15:02,735 --> 00:15:03,485
passenger airplanes

480
00:15:03,485 --> 00:15:04,987
that people fly on every day

481
00:15:04,987 --> 00:15:06,071
and using that

482
00:15:06,071 --> 00:15:07,489
to give us a reliable picture

483
00:15:07,489 --> 00:15:08,324
of what's happening

484
00:15:08,324 --> 00:15:09,950
with today's conditions

485
00:15:09,950 --> 00:15:11,744
so we can make a reliable prediction

486
00:15:11,744 --> 00:15:12,620
into the future

487
00:15:12,620 --> 00:15:14,747
to inform people all over the world

488
00:15:14,747 --> 00:15:16,415
how weather is changing.

489
00:15:16,415 --> 00:15:17,291
And we do the same thing

490
00:15:17,291 --> 00:15:18,375
for seasonal predictions.

491
00:15:18,375 --> 00:15:19,752
So we can predict things

492
00:15:19,752 --> 00:15:21,045
nine months into the future

493
00:15:21,045 --> 00:15:22,421
and give people some sense

494
00:15:22,421 --> 00:15:24,423
of how seasonal temperatures

495
00:15:24,423 --> 00:15:26,592
might evolve.

496
00:15:33,432 --> 00:15:34,600
So one thing that's really

497
00:15:34,600 --> 00:15:35,601
exciting about models

498
00:15:35,601 --> 00:15:37,478
is the whole landscape of models

499
00:15:37,478 --> 00:15:39,897
has changed, both with the availability

500
00:15:39,897 --> 00:15:40,606
of high performance

501
00:15:40,606 --> 00:15:42,191
computing supercomputers

502
00:15:42,191 --> 00:15:44,360
and the availability of satellite data.

503
00:15:44,360 --> 00:15:45,194
So some of the things

504
00:15:45,194 --> 00:15:46,737
that we're able to do with models

505
00:15:46,737 --> 00:15:47,947
we couldn't do five

506
00:15:47,947 --> 00:15:49,657
even ten years ago,

507
00:15:49,657 --> 00:15:51,367
things like running models

508
00:15:51,367 --> 00:15:52,326
and much finer

509
00:15:52,326 --> 00:15:54,078
spatial scales to understand

510
00:15:54,078 --> 00:15:54,870
how conditions

511
00:15:54,870 --> 00:15:57,206
are changing in local areas, urban areas,

512
00:15:57,206 --> 00:15:58,749
even within neighborhoods.

513
00:15:58,749 --> 00:16:00,167
The other thing that's really changing

514
00:16:00,167 --> 00:16:01,877
is the complexity of processes

515
00:16:01,877 --> 00:16:02,586
and models.

516
00:16:02,586 --> 00:16:03,879
Used to be that we had one model

517
00:16:03,879 --> 00:16:04,964
that would tell us about weather,

518
00:16:04,964 --> 00:16:06,131
and then we had to take that data,

519
00:16:06,131 --> 00:16:07,424
plug it into a separate model

520
00:16:07,424 --> 00:16:08,968
that would tell us about greenhouse gases

521
00:16:08,968 --> 00:16:10,177
and air quality.

522
00:16:10,177 --> 00:16:11,470
Today's models include

523
00:16:11,470 --> 00:16:13,931
all of those processes at the same time.

524
00:16:13,931 --> 00:16:14,682
That's important

525
00:16:14,682 --> 00:16:16,433
for having the most accuracy

526
00:16:16,433 --> 00:16:17,017
and being able

527
00:16:17,017 --> 00:16:18,060
to provide the best

528
00:16:18,060 --> 00:16:19,603
and most integrated information

529
00:16:19,603 --> 00:16:21,063
that helps policymakers

530
00:16:21,063 --> 00:16:23,399
navigate a number of climate

531
00:16:23,399 --> 00:16:25,985
related challenges all at once.

532
00:16:32,700 --> 00:16:34,034
So models are an incredibly

533
00:16:34,034 --> 00:16:35,077
important component

534
00:16:35,077 --> 00:16:38,080
of helping us understand and navigate

535
00:16:38,288 --> 00:16:39,289
a warming climate.

536
00:16:39,289 --> 00:16:40,666
But I want people to understand that

537
00:16:40,666 --> 00:16:41,625
when we talk about temperature

538
00:16:41,625 --> 00:16:43,919
change, global temperature

539
00:16:43,919 --> 00:16:46,005
changes over the past 250 years,

540
00:16:46,005 --> 00:16:48,007
that knowledge is grounded

541
00:16:48,007 --> 00:16:50,759
in observations taking at ground stations

542
00:16:50,759 --> 00:16:52,428
across the world, in some cases

543
00:16:52,428 --> 00:16:54,304
satellite data as well.

544
00:16:54,304 --> 00:16:55,764
But really

545
00:16:55,764 --> 00:16:56,640
the observations

546
00:16:56,640 --> 00:16:58,267
are the basis of understanding

547
00:16:58,267 --> 00:16:58,934
and documenting

548
00:16:58,934 --> 00:17:00,394
how the planet has changed.

549
00:17:00,394 --> 00:17:01,687
Now, using those observations,

550
00:17:01,687 --> 00:17:03,272
we create better models.

551
00:17:03,272 --> 00:17:04,857
Those models can help us understand

552
00:17:04,857 --> 00:17:06,734
things that we can't observe directly,

553
00:17:06,734 --> 00:17:08,360
like why the climate is changing,

554
00:17:08,360 --> 00:17:09,069
what are the relative

555
00:17:09,069 --> 00:17:11,280
contributions of natural factors

556
00:17:11,280 --> 00:17:12,448
and human factors.

557
00:17:12,448 --> 00:17:13,824
And really importantly,

558
00:17:13,824 --> 00:17:15,284
given an amount of warming,

559
00:17:15,284 --> 00:17:16,869
how is that going to change

560
00:17:16,869 --> 00:17:18,287
the trajectory of the planet in

561
00:17:18,287 --> 00:17:20,664
coming decades and centuries?

562
00:17:27,504 --> 00:17:28,338
know, it's really tricky.

563
00:17:28,338 --> 00:17:29,465
We have computer models

564
00:17:29,465 --> 00:17:30,883
and in a lot of cases

565
00:17:30,883 --> 00:17:32,676
we know a lot more in terms of science

566
00:17:32,676 --> 00:17:33,552
and we can actually write

567
00:17:33,552 --> 00:17:35,262
and solve in terms of these equations

568
00:17:35,262 --> 00:17:37,347
because it's a lot of compute power,

569
00:17:37,347 --> 00:17:39,767
a lot of energy to make those models go.

570
00:17:39,767 --> 00:17:41,060
Some of the things that we know

571
00:17:41,060 --> 00:17:42,061
we want to understand

572
00:17:42,061 --> 00:17:43,395
and increase the complexity

573
00:17:43,395 --> 00:17:44,646
of in these projection

574
00:17:44,646 --> 00:17:45,397
models

575
00:17:45,397 --> 00:17:47,107
are the interactions between

576
00:17:47,107 --> 00:17:47,983
tiny particles

577
00:17:47,983 --> 00:17:49,068
called aerosols

578
00:17:49,068 --> 00:17:49,902
and clouds,

579
00:17:49,902 --> 00:17:51,695
because those are really important

580
00:17:51,695 --> 00:17:53,113
in changing

581
00:17:53,113 --> 00:17:55,449
how clouds either

582
00:17:55,449 --> 00:17:57,618
trap or reflect radiation.

583
00:17:57,618 --> 00:17:58,994
So it really affects the way

584
00:17:58,994 --> 00:18:00,287
that climate change

585
00:18:00,287 --> 00:18:01,872
progresses, also affects things

586
00:18:01,872 --> 00:18:03,832
like the formation of storms.

587
00:18:03,832 --> 00:18:04,750
Another area

588
00:18:04,750 --> 00:18:05,709
where we would like to have

589
00:18:05,709 --> 00:18:07,127
a lot more information

590
00:18:07,127 --> 00:18:08,087
is the way

591
00:18:08,087 --> 00:18:11,590
that the natural sinks of carbon

592
00:18:11,590 --> 00:18:12,883
dioxide on the land in

593
00:18:12,883 --> 00:18:15,427
the ocean are affected by climate change.

594
00:18:15,427 --> 00:18:16,887
So right now,

595
00:18:16,887 --> 00:18:18,806
trees and the world's oceans

596
00:18:18,806 --> 00:18:19,723
absorb about half

597
00:18:19,723 --> 00:18:21,975
of our pollution of carbon dioxide,

598
00:18:21,975 --> 00:18:23,685
and it's giving us a huge assist

599
00:18:23,685 --> 00:18:25,062
in terms of climate change.

600
00:18:25,062 --> 00:18:25,854
But one of the things

601
00:18:25,854 --> 00:18:27,272
that's a big source of uncertainty

602
00:18:27,272 --> 00:18:29,108
is how long that can continue

603
00:18:29,108 --> 00:18:30,818
and how are things like fires

604
00:18:30,818 --> 00:18:32,027
and droughts and more stress

605
00:18:32,027 --> 00:18:32,986
on vegetation

606
00:18:32,986 --> 00:18:35,114
influencing that ability to absorb

607
00:18:35,114 --> 00:18:38,075
and help us out with climate change.

608
00:18:45,332 --> 00:18:46,208
So one thing that's really

609
00:18:46,208 --> 00:18:47,543
important for people to understand

610
00:18:47,543 --> 00:18:48,585
when we talk about

611
00:18:48,585 --> 00:18:50,295
global temperature rise

612
00:18:50,295 --> 00:18:52,297
is that we're talking about the increase

613
00:18:52,297 --> 00:18:53,882
in global mean temperature,

614
00:18:53,882 --> 00:18:54,967
but that doesn't mean you're

615
00:18:54,967 --> 00:18:56,176
not going to have an extreme winter.

616
00:18:56,176 --> 00:18:56,677
It doesn't mean

617
00:18:56,677 --> 00:18:59,304
you might not have a big snowstorm

618
00:18:59,304 --> 00:19:00,848
in your area. Right.

619
00:19:00,848 --> 00:19:02,141
Because that means that temperatures

620
00:19:02,141 --> 00:19:03,142
across the world

621
00:19:03,142 --> 00:19:04,393
as an aggregate

622
00:19:04,393 --> 00:19:05,227
are getting warmer

623
00:19:05,227 --> 00:19:06,770
and marching steadily upwards.

624
00:19:06,770 --> 00:19:07,813
But still,

625
00:19:07,813 --> 00:19:09,231
there's natural variability

626
00:19:09,231 --> 00:19:11,316
from year to year, season to season.

627
00:19:11,316 --> 00:19:12,651
There's spatial variability

628
00:19:12,651 --> 00:19:13,152
with warming,

629
00:19:13,152 --> 00:19:14,653
concentrating in some areas

630
00:19:14,653 --> 00:19:16,238
like the higher latitudes

631
00:19:16,238 --> 00:19:17,197
of the northern hemisphere

632
00:19:17,197 --> 00:19:17,739
that are warming

633
00:19:17,739 --> 00:19:19,283
more rapidly than others.

634
00:19:19,283 --> 00:19:20,742
So there's all this complexity

635
00:19:20,742 --> 00:19:21,743
from different regions

636
00:19:21,743 --> 00:19:22,536
that are experiencing

637
00:19:22,536 --> 00:19:24,163
climate change in different ways.

638
00:19:24,163 --> 00:19:27,666
And some people confuse that with

639
00:19:27,749 --> 00:19:28,917
the idea that global

640
00:19:28,917 --> 00:19:30,294
temperature isn't increasing.

641
00:19:30,294 --> 00:19:31,211
So that's an important thing

642
00:19:31,211 --> 00:19:32,629
for people to understand and relating

643
00:19:32,629 --> 00:19:33,797
what might be happening

644
00:19:33,797 --> 00:19:34,840
in your own environment

645
00:19:34,840 --> 00:19:36,466
with what's happening to the planet

646
00:19:36,466 --> 00:19:37,509
as a whole.

647
00:19:44,391 --> 00:19:45,809
You know, when people ask questions

648
00:19:45,809 --> 00:19:46,393
like this,

649
00:19:46,393 --> 00:19:47,269
I think it's important

650
00:19:47,269 --> 00:19:48,187
to understand

651
00:19:48,187 --> 00:19:49,730
that everybody has individual answers

652
00:19:49,730 --> 00:19:50,981
and everybody is experiencing

653
00:19:50,981 --> 00:19:52,608
climate change from a different lens.

654
00:19:52,608 --> 00:19:54,067
It's affected by where you live.

655
00:19:54,067 --> 00:19:55,068
It's affected by

656
00:19:55,068 --> 00:19:57,112
just the way that you tackle problems.

657
00:19:57,112 --> 00:19:58,280
But for me,

658
00:19:58,280 --> 00:19:59,781
I tend to look at the positives

659
00:19:59,781 --> 00:20:01,033
and I see a lot of attention.

660
00:20:01,033 --> 00:20:02,201
I see a lot of people

661
00:20:02,201 --> 00:20:04,703
working hard and understanding

662
00:20:04,703 --> 00:20:06,038
that climate change is serious

663
00:20:06,038 --> 00:20:07,039
and that we have to do something

664
00:20:07,039 --> 00:20:07,748
about it,

665
00:20:07,748 --> 00:20:08,165
you know, 5

666
00:20:08,165 --> 00:20:08,874
to 10 years ago

667
00:20:08,874 --> 00:20:10,000
when I used to do interviews,

668
00:20:10,000 --> 00:20:12,127
people would say, Is climate change real?

669
00:20:12,127 --> 00:20:13,337
And I don't get that reaction

670
00:20:13,337 --> 00:20:14,713
very much anymore.

671
00:20:14,713 --> 00:20:16,506
I get the question, is it too late?

672
00:20:16,506 --> 00:20:17,507
What can I do?

673
00:20:17,507 --> 00:20:19,718
How do I team up with my neighbors

674
00:20:19,718 --> 00:20:20,260
to help?

675
00:20:20,260 --> 00:20:22,638
And so that gives me some hope

676
00:20:22,638 --> 00:20:24,598
that people are taking this seriously.

677
00:20:24,598 --> 00:20:26,141
I think we see evidence of that

678
00:20:26,141 --> 00:20:27,142
in some of the

679
00:20:27,142 --> 00:20:29,394
the emissions reduction measures

680
00:20:29,394 --> 00:20:30,229
that are being imposed

681
00:20:30,229 --> 00:20:31,188
across the world

682
00:20:31,188 --> 00:20:33,357
and the actions that are being taken

683
00:20:33,357 --> 00:20:34,691
not just at large

684
00:20:34,691 --> 00:20:36,360
administrative countries scales,

685
00:20:36,360 --> 00:20:38,445
but within communities within cities.

686
00:20:38,445 --> 00:20:40,364
Some of the cities are around the world.

687
00:20:40,364 --> 00:20:41,114
Are the leaders

688
00:20:41,114 --> 00:20:43,158
in reducing greenhouse gases,

689
00:20:43,158 --> 00:20:45,160
working to reduce them even more quickly

690
00:20:45,160 --> 00:20:46,662
than the countries that they're parts of?

691
00:20:46,662 --> 00:20:47,162
Right.

692
00:20:47,162 --> 00:20:48,664
So you see these smaller

693
00:20:48,664 --> 00:20:49,581
collective actions

694
00:20:49,581 --> 00:20:50,290
that can add up

695
00:20:50,290 --> 00:20:51,541
to a really big difference.

696
00:20:51,541 --> 00:20:52,709
And those are some of the reasons

697
00:20:52,709 --> 00:20:54,586
that even though yeah, we have to admit

698
00:20:54,586 --> 00:20:56,088
that this is a serious problem

699
00:20:56,088 --> 00:20:57,589
and we have to tackle it,

700
00:20:57,589 --> 00:20:59,591
I am hopeful and I do see change.