It's not by their farts, but it's by belching.

Cook: "A few degrees' difference is not a big deal."

And the way I always like to think about it too

is like your body's temperature.

If your temperature is three or four degrees warmer,

then you're seriously sick.

"It's too late to do anything about it."

Unless you're Elon Musk

and gonna head off towards Mars,

we're all stuck here,

so we should try to figure out

how we can make it the best planet we can.

I'm Deepti Singh.

I'm an assistant professor

in the School of the Environment

at Washington State University.

I've been studying climate change for about 11 years,

and I study extreme weather events

and how human activities are influencing them.

My name is Benjamin Cook, and I'm a climate scientist

at the NASA Goddard Institute for Space Studies.

I've been working there for about 14 years now.

And I study how droughts are changing

with global warming and climate change.

And today we'll be debunking myths about global warming.

Cook: Myths from pop culture.

Oh, boy, I'm glad you got this one, Deepti.

"The sun is causing global warming."

Changes in the amount of energy we get from the sun

do affect our climate.

But over the last 150 years, we know that

because the amount of energy we're getting from the sun

has not changed significantly over this period.

Satellites have been recording

the amount of solar radiation that our planet receives.

I think Ben has a graph that shows that.

Cook: And what we're looking at here on the yellow

is the amount of energy that's coming from the sun,

and red is global temperatures.

It's pretty clear that the amount of energy

we're getting from the sun has been more or less flat

for the last several decades,

even as temperatures continue to go up and up.

Singh: "Scientists don't agree

on what causes climate change."

100% of the climate scientists on this Skype call agree.

If you review the published literature

in reputable journals by reputable scientists,

all those papers agree

that climate change is caused by human activities.

There's really no other explanation that fits the data.

We've looked at the sun.

We've looked at just natural variations

in circulation in the ocean, in the atmosphere.

We've looked at volcanoes.

We've looked at changes in ecosystems.

And at the end of the day, the only thing

that can adequately explain the degree of warming

that we've seen over the last 150 years

is human greenhouse gas emissions,

primarily through the burning of fossil fuels.

There's a real clear incentive

for people to find some other explanation.

Nobody can come up with

even a plausible alternative hypothesis.

"Global warming is caused by cow farts."

It's not by their farts, but it's by belching.

Agriculture is a pretty substantial contributor

to greenhouse gas emissions, close to 25%.

It's not the whole 25%, but it's a good chunk.

It's important to note, too, that even the cow burps

that are producing this methane is not natural.

It's all part of a kind of human agricultural system.

So blaming it all on cows

doesn't take people off the hook.

"Plants and animals will adapt."

So, we know that in the past,

plants and animals have adapted to climate change,

but there's a few fundamental different things now

that are very likely to make it quite difficult.

In addition, it's not just climate change

that's threatening plants and animals,

it's habitat fragmentation,

it's pollution,

it's a variety of other environmental stressors.

And so once you kind of put climate change

on top of pollution, on top of habitat loss,

then it becomes much, much more difficult.

And just to add to that,

I think the extinction rate of species is much higher

than the natural extinction rate.

And it's partly driven by

the processes that Ben just mentioned.

Cook: Myths from social media.

"Global warming is natural."

So, we know in the past that climate can change

really dramatically from natural causes.

The climate during the time of the dinosaurs

is very different from the climate

during the time of the last ice age.

But the changes that we're seeing right now

for the most part are not natural.

The warming that we're seeing is very likely

the fastest warming we've seen

anytime in the last several thousand years.

It coincides directly with the industrial revolution

and the burning of fossil fuels

and widespread deforestation.

You can look at almost any natural cause,

and none of them are sufficient to explain

the warming that we've seen in recent decades.

"Carbon dioxide is the problem."

So, CO2 isn't the problem.

It's the increase in the concentration of CO2

in the atmosphere that is resulting

in the rapid warming we're seeing

over the last century, which is the problem.

So, carbon dioxide is one of these gases

that we call greenhouse gases,

because they're responsible for the greenhouse effect,

which basically helps trap energy on Earth

and make things much, much warmer

than it otherwise would have been.

It's not a big stretch then to observe

that if we start increasing CO2 concentrations,

we're gonna trap more energy and we're gonna warm up.

Before the industrial revolution,

CO2 levels were close to, like, 280 parts per million.

And now we're at close to 418 parts per million.

So that's a pretty large change in the concentration.

And the fact is that pretty much anytime

the world was warmer,

CO2 levels in the atmosphere were higher.

And anytime the world was cooler,

CO2 concentrations were lower.

"A few degrees' difference is not a big deal."

And the way I always like to think about it too

is like your body's temperature.

We're all supposed to be about 98.6 degrees Fahrenheit.

Even one degree or two degrees of warming

is considered a low-grade fever.

And if your temperature is three or four degrees warmer,

then you're seriously sick.

So, just to give you a sense,

the Earth has warmed by about one degree

over the last century.

That one degree is an average temperature around our planet.

That means some parts of our planet

are warming faster than others.

I come from India.

We have a lot of people

that live below poverty in the country.

And most of those people, for example,

don't have an air conditioner

to deal with extreme heat events.

So it depends on who we're talking about

when we say it's not a big deal,

because there are some people around the planet

that have the capacity to adapt or cope

with these kind of extreme events

and with the warming that we've experienced,

and then there are billions of people

that do not have the capacity to cope

with even small changes.

Myths that we, climate scientists, hear the most.

"Global warming will destroy the planet by 2030."

Just like there's kind of climate deniers

who don't know what they're talking about,

there's climate doomists

who also don't know what they're talking about.

This whole idea of the planet

being destroyed by 2030 comes out of discussion

about, how much time do we have

to keep global warming under two degrees?

And so it's very likely that we need to

kind of get emissions under control by 2030

to keep it under two degrees.

It doesn't mean that the world is going to explode

or we're all going to be consigned

to a fiery "Mad Max" kind of hellscape.

It just means that it'll be warmer

than we maybe wanted it to be.

When they say it's gonna destroy the planet,

well, the planet's not going to blow up.

But it does mean that the way of life

and the livelihoods

and the things people depend on

are going to be affected.

There are already people who have been displaced

because of sea-level rise,

people that are experiencing

life-threatening heat conditions.

The impacts of climate change

are not going to be equally felt.

These kind of blanket statements

are very, very dismissive.

And I think they can take attention

away from the people who are likely to be

most vulnerable to climate change.

It's not really helpful to put a date on it.

I think we just need to know that

delaying action on climate change

is going to just cost more to society.

Cook: "Global warming is China's fault."

So, to address that myth,

I think there's one important fact we need to understand.

When CO2 is emitted,

it can stay in the atmosphere for hundreds,

if not thousands of years.

The CO2 concentrations we're seeing today

are a consequence of emissions that have happened

over a much longer period, over the last century.

And most of those emissions are associated

with the industrial revolution

and development of countries like the US

and industrialized nations in Europe.

If we look at emissions this year specifically,

sure, the emissions from China

are close to what the emissions from the US are.

But those emissions are being used

to produce products and goods

that are being used in other parts of the world.

So I don't think it's fair to say

that China's responsible

when we're all benefiting from the products

that are produced there.

I think even today, it's worth thinking

not just about how much is a country emitting,

but how much are they emitting per person?

And I have another visual aid here.

You can pretty clearly see

the highest-intensity emitters

are places like Australia,

the US, Canada, Russia, Saudi Arabia.

China isn't even in the top 10.

It's also a complicated problem

because the well-being of people

is tied to their consumption of energy.

So as long as we're doing that

in a sustainable, cleaner way,

I think we all have to benefit from it.

"Renewable energy is too expensive to be realistic."

Renewable energy is getting cheaper all the time,

even faster than we expected.

And there's a lot of places

where it actually can outcompete some fossil fuel sources.

For example, I believe wind and solar

is more cost-effective than coal

in pretty much the entire United States.

The cost of producing solar panels today

is a fraction of what it was just a decade ago.

I keep going back to India

because that's another region I'm very familiar with.

There are a lot of villages there