theme, and then I found out I'm leading off the "Nightmare?" section of it.

(Laughter)

And certainly there are things about the climate

crisis that qualify. And I have some bad news, but I have a lot more good news. I'm going

to propose three questions and the answer to the first one necessarily involves a little

bad news. But -- hang on, because the answers to the second and third questions really are

very positive.

So the first question is, "Do we really have to change?" And of course, the Apollo Mission,

among other things changed the environmental movement, really launched the modern environmental

movement 18 months after this Earthrise picture was first seen on earth, the first Earth Day

was organized. And we learned a lot about ourselves looking back at our planet from

space. And one of the things that we learned confirmed what the scientists have long told

us. One of the most essential facts about the climate crisis has to do with the sky.

As this picture illustrates, the sky is not the vast and limitless expanse that appears

when we look up from the ground. It is a very thin shell of atmosphere surrounding the planet.

That right now is the open sewer for our industrial civilization as it's currently organized.

We are spewing 110 million tons of heat-trapping global warming pollution into it every 24

hours, free of charge, go ahead.

And there are many sources of the greenhouse gases, I'm certainly not going to go through

them all. I'm going to focus on the main one, but agriculture is involved, diet is involved,

population is involved. Management of forests, transportation, the oceans, the melting of

the permafrost. But I'm going to focus on the heart of the problem, which is the fact

that we still rely on dirty, carbon-based fuels for 85 percent of all the energy that

our world burns every year. And you can see from this image that after World War II, the

emission rates started really accelerating. And the accumulated amount of man-made, global

warming pollution that is up in the atmosphere now traps as much extra heat energy as would

be released by 400,000 Hiroshima-class atomic bombs exploding every 24 hours, 365 days a

year. Fact-checked over and over again, conservative, it's the truth. Now it's a big planet, but

--

(Explosion sound)

that is a lot of energy, particularly when you multiply it 400,000 times per day. And

all that extra heat energy is heating up the atmosphere, the whole earth system.

Let's look at the atmosphere. This is a depiction

of what we used to think of as the normal distribution of temperatures. The white represents

normal temperature days; 1951-1980 are arbitrarily chosen. The blue are cooler than average days,

the red are warmer than average days. But the entire curve has moved to the right in

the 1980s. And you'll see in the lower right-hand corner the appearance of statistically significant

numbers of extremely hot days. In the 90s, the curve shifted further. And in the last

10 years, you see the extremely hot days are now more numerous than the cooler than average

days. In fact, they are 150 times more common on the surface of the earth than they were

just 30 years ago.

So we're having record-breaking temperatures. Fourteen of the 15 of the hottest years ever

measured with instruments have been in this young century. The hottest of all was last

year. Last month was the 371st month in a row warmer than the 20th-century average.

And for the first time, not only the warmest January, but for the first time, it was more

than two degrees Fahrenheit warmer than the average. These higher temperatures are having

an effect on animals, plants, people, ecosystems.

But on a global basis, 93 percent of all the extra heat energy is trapped in the oceans.

And the scientists can measure the heat buildup much more precisely now at all depths: deep,

mid-ocean, the first few hundred meters. And this, too, is accelerating. It goes back more

than a century. And more than half of the increase has been in the last 19 years. This

has consequences.

The first order of consequence: the ocean-based storms get stronger. Super Typhoon Haiyan

went over areas of the Pacific five and a half degrees Fahrenheit warmer than normal

before it slammed into Tacloban, as the most destructive storm ever to make landfall. Pope

Francis, who has made such a difference to this whole issue, visited Tacloban right after

that. Superstorm Sandy went over areas of the Atlantic nine degrees warmer than normal

before slamming into New York and New Jersey. The second order of consequences are affecting

all of us right now. The warmer oceans are evaporating much more water vapor into the

skies. Average humidity worldwide has gone up four percent. And it creates these atmospheric

rivers. The Brazilian scientists call them "flying rivers." And they funnel all of that

extra water vapor over the land where storm conditions trigger these massive record-breaking

downpours. This is from Montana. Take a look at this storm last August. As it moves over

Tucson, Arizona. It literally splashes off the city. These downpours are really unusual.

Last July in Houston, Texas, it rained for

two days, 162 billion gallons. That represents more than two days of the full flow of Niagara

Falls in the middle of the city, which was, of course, paralyzed. These record downpours

are creating historic floods and mudslides.

This one is from Chile last year. And you'll see that warehouse going by. There are oil

tankers cars going by. This is from Spain last September, you could call this the running

of the cars and trucks, I guess. Every night on the TV news now is like a nature hike through

the Book of Revelation.

(Laughter)

I mean, really.

The insurance industry has certainly noticed, the losses have been mounting up. They're

not under any illusions about what's happening. And the causality requires a moment of discussion.

We're used to thinking of linear cause and linear effect -- one cause, one effect. This

is systemic causation. As the great Kevin Trenberth says, "All storms are different

now. There's so much extra energy in the atmosphere, there's so much extra water vapor. Every storm

is different now." So, the same extra heat pulls the soil moisture out of the ground

and causes these deeper, longer, more pervasive droughts and many of them are underway right

now.

It dries out the vegetation and causes more fires in the western part of North America.

There's certainly been evidence of that, a lot of them.

More lightning, as the heat energy builds

up, a considerable amount of additional lightning also.

These climate-related disasters also have

geopolitical consequences and create instability. The climate-related historic drought that

started in Syria in 2006 destroyed 60 percent of the farms in Syria, killed 80 percent of

the livestock, and drove 1.5 million climate refugees into the cities of Syria, where they

collided with another 1.5 million refugees from the Iraq War. And along with other factors,

that opened the gates of Hell that people are trying to close now. The US Defense Department

has long warned of consequences from the climate crisis, including refugees, food and water

shortages and pandemic disease.

Right now we're seeing microbial diseases from the tropics spread to the higher latitudes;

the transportation revolution has had a lot to do with this. But the changing conditions

change the latitudes in the areas where these microbial diseases can become endemic and

change the range of the vectors, like mosquitoes and ticks that carry them. The Zika epidemic

now -- we're better positioned in North America because it's still a little too cool and we

have a better public health system. But when women in some regions of South and Central

America are advised not to get pregnant for two years -- that's something new, that ought

to get our attention. The Lancet, one of the two greatest medical journals in the world,

last summer labeled this a medical emergency now. And there are many factors because of

it.

This is also connected to the extinction crisis. We're in danger of losing 50 percent of all

the living species on earth by the end of this century. And already, land-based plants

and animals are now moving towards the poles at an average rate of 15 feet per day.

Speaking of the North Pole, last December

29, the same storm that caused historic flooding in the American Midwest, raised temperatures

at the North Pole 50 degrees Fahrenheit warmer than normal, causing the thawing of the North

Pole in the middle of the long, dark, winter, polar night. And when the land-based ice of

the Arctic melts, it raises sea level.

Paul Nicklen's beautiful photograph from Svalbard illustrates this. It's more dangerous coming

off Greenland and particularly, Antarctica. The 10 largest risk cities for sea-level rise

by population are mostly in South and Southeast Asia. When you measure it by assets at risk,

number one is Miami: three and a half trillion dollars at risk. Number three: New York and

Newark. I was in Miami last fall during the supermoon, one of the highest high-tide days.

And there were fish from the ocean swimming in some of the streets of Miami Beach and

Fort Lauderdale and Del Rey. And this happens regularly during the highest-tide tides now.

Not with rain -- they call it "sunny-day flooding." It comes up through the storm sewers. And

the Mayor of Miami speaks for many when he says it is long past time this can be viewed

through a partisan lens. This is a crisis that's getting worse day by day. We have to

move beyond partisanship.

And I want to take a moment to honor these House Republicans --

(Applause)

who had the courage last fall to step out

and take a political risk, by telling the truth about the climate crisis.

So the cost of the climate crisis is mounting

up, there are many of these aspects I haven't even mentioned. It's an enormous burden. I'll

mention just one more, because the World Economic Forum last month in Davos, after their annual

survey of 750 economists, said the climate crisis is now the number one risk to the global

economy. So you get central bankers like Mark Carney, the head of the UK Central Bank, saying

the vast majority of the carbon reserves are unburnable. Subprime carbon. I'm not going

to remind you what happened with subprime mortgages, but it's the same thing. If you

look at all of the carbon fuels that were burned since the beginning of the industrial

revolution, this is the quantity burned in the last 16 years. Here are all the ones that

are proven and left on the books, 28 trillion dollars. The International Energy Agency says

only this amount can be burned. So the rest, 22 trillion dollars -- unburnable. Risk to

the global economy. That's why divestment movement makes practical sense and is not

just a moral imperative.

So the answer to the first question, "Must we change?" is yes, we have to change. Second

question, "Can we change?" This is the exciting news! The best projections in the world 16

years ago were that by 2010, the world would be able to install 30 gigawatts of wind capacity.

We beat that mark by 14 and a half times over. We see an exponential curve for wind installations

now. We see the cost coming down dramatically. Some countries -- take Germany, an industrial

powerhouse with a climate not that different from Vancouver's, by the way -- one day last

December, got 81 percent of all its energy from renewable resources, mainly solar and

wind. A lot of countries are getting more than half on an average basis.

More good news: energy storage, from batteries

particularly, is now beginning to take off because the cost has been coming down very

dramatically to solve the intermittency problem. With solar, the news is even more exciting!

The best projections 14 years ago were that we would install one gigawatt per year by

2010. When 2010 came around, we beat that mark by 17 times over. Last year, we beat

it by 58 times over. This year, we're on track to beat it 68 times over.

We're going to win this. We are going to prevail.

The exponential curve on solar is even steeper and more dramatic. When I came to this stage

10 years ago, this is where it was. We have seen a revolutionary breakthrough in the emergence

of these exponential curves.

(Applause)

And the cost has come down 10 percent per year for 30 years. And it's continuing to

come down.

Now, the business community has certainly noticed this, because it's crossing the grid

parity point. Cheaper solar penetration rates are beginning to rise. Grid parity is understood

as that line, that threshold, below which renewable electricity is cheaper than electricity

from burning fossil fuels. That threshold is a little bit like the difference between

32 degrees Fahrenheit and 33 degrees Fahrenheit, or zero and one Celsius. It's a difference

of more than one degree, it's the difference between ice and water. And it's the difference

between markets that are frozen up, and liquid flows of capital into new opportunities for

investment. This is the biggest new business opportunity in the history of the world, and

two-thirds of it is in the private sector. We are seeing an explosion of new investment.

Starting in 2010, investments globally in renewable electricity generation surpassed

fossils. The gap has been growing ever since. The projections for the future are even more

dramatic, even though fossil energy is now still subsidized at a rate 40 times larger

than renewables. And by the way, if you add the projections for nuclear on here, particularly

if you assume that the work many are doing to try to break through to safer and more

acceptable, more affordable forms of nuclear, this could change even more dramatically.

So is there any precedent for such a rapid

adoption of a new technology? Well, there are many, but let's look at cell phones. In

1980, AT&T, then Ma Bell, commissioned McKinsey to do a global market survey of those clunky

new mobile phones that appeared then. "How many can we sell by the year 2000?" they asked.

McKinsey came back and said, "900,000." And sure enough, when the year 2000 arrived, they

did sell 900,000 -- in the first three days. And for the balance of the year, they sold

120 times more. And now there are more cell connections than there are people in the world.