Thank you very much.

When I was a boy,

my parents would sometimes
take me camping in California.

We would camp in the beaches,
in the forests, in the deserts.

Some people think the deserts
are empty of life

but my parents taught me
to see the wildlife all around us:

the hawks, the eagles, the tortoises.

One time when we were setting up camp,

we found a baby scorpion
with its stinger out,

and I remember thinking how cool it was

that something could be
both so cute and also so dangerous.

After college, I moved to California

and I started working on a number
of environmental campaigns,

I got involved in helping to save
the state's last ancient redwood forests

and blocking a proposed radioactive
waste repository set for the desert.

Shortly after I turned 30,

I decided I wanted to dedicate
a significant amount of my life

to solving climate change.

I was worried that global warming
would end up destroying

many of the natural environments

that people had worked
so hard to protect.

I thought the technical solutions
were pretty straightforward;

solar panels on every roof,
electric car in the driveway,

that the main obstacles were political.

And so I helped to organize a coalition

of the country's biggest labor unions
and biggest environmental groups.

Our proposal was for a 300 billion
dollar investment in renewables.

And the idea was not only
would we prevent climate change,

but we would also create
millions of new jobs

in a very fast-growing high-tech sector.

Our efforts really paid off in 2007,

when then-presidential candidate
Barack Obama embraced our vision.

And between 2009 and 2015,
the US invested 150 billion dollars

in renewables and other
kinds of clean tech.

but right away we started
to encounter some problems.

So first of all, the electricity
from solar rooftops

ends up costing about twice as much
as the electricity from solar farms.

And both solar farms and wind farms
require covering a pretty significant

amount of land with solar panels
and wind turbines

and also building
very big transmission lines

to bring all that electricity
from the countryside into the city.

Both of those things were often very
strongly resisted by local communities,

as well as by conservation biologists

who were concerned about the impacts
on wild bird species and other animals.

Now, there was a lot of other people

working on technical
solutions at the time.

One of the big challenges, of course,

is just the intermittency
of solar and wind

they only generate electricity
about 10 to 30 percent of the time

during most of year.

But some of the solutions
that were being proposed

were to convert hydroelectric
dams into gigantic batteries.

The idea was that

when the sun was shining
and the wind was blowing,

you would pump
the water uphill, store it for later

and then when you needed electricity,
run it over the turbines.

In terms of wildlife,

some of these problems just didn't
seem like a significant concern.

So when I learned that house cats
kill billions of birds every year

it put into perspective the hundreds
of thousands of birds

that are killed by wind turbines.

It basically seemed to me at the time

that most, if not all, of the problems
of scaling up solar and wind

could be solved through more
technological innovation.

But as the years went by,

these problems persisted
and, in many cases, grew worse.

So California is a state that's really
committed to renewable energy,

but we still haven't converted
many of our hydroelectric dams

into big batteries.

Some of the problems are just Geographic;

it's just you have to have
a very particular kind of formation

to be able to do that,

and even in those cases,

it's quite expensive
to make those conversions.

Other challenges are just
that there're other uses for water

like irrigation,

and maybe the most significant
problem is just that in California,

the water in our rivers and reservoirs

is growing increasingly
scarce and unreliable

due to climate change.

In terms of this issue of reliability
as a consequence of it,

we've actually had to stop the electricity
coming from the solar farms into the cities

because there's just been
too much of it at times.

Or we've been starting to pay
our neighboring states like Arizona

to take that solar electricity.

The alternative is to suffer
from blowouts of the grid.

And it turns out that

when it comes to birds and cats -

cats don't kill eagles; eagles kill cats.

What cats kill are the small common
sparrows and Jay's and robins,

birds that are not endangered
and not at risk of going extinct.

What do kill eagles and other big birds
like this kite as well as owls and condors

and other threatened
and endangered species

are wind turbines-

in fact, one of the most significant threats
to those big bird species that we have -

we just haven't been introducing
the airspace with many other objects

like we have wind turbines

over the last several years.

And in terms of solar,

you know building a solar farm
is a lot like building any other kind of farm

You have to clear
the whole area of wildlife.

So this is a picture of one third of one
of the biggest solar farms in California

called Ivanpah.

In order to build this,

they had to clear
the whole area of desert tortoises -

literally pulling desert tortoises -

and their babies out of burrows

putting them on the back of pickup trucks,
and transporting them to captivity

where many of them ended up dying.

And currently, the current estimates are
that about 6,000 birds are killed every year,

actually catching on fire above the solar farm
and plunging to their deaths.

Over time it gradually struck me

that there was really no amount
of technological innovation

that was going to make
the sunshine more regularly

or wind blow more reliably.

In fact, nothing could you could make solar

panels cheaper you could make wind

turbines bigger but sunlight and wind

are just really dilute fuels and in

order to produce significant amounts of

electricity

you just have to cover a very large land

mass with them in other words all of the

major problems with renewables aren't

technical they're natural well dealing

with all of this unreliability and the

big environmental impacts obviously

comes at a pretty high economic cost you

know we've been hearing a lot about how

solar panels and wind turbines have come

down in cost in recent years but that

cost has been significantly outweighed

by just the challenges of integrating

all of that unreliable power onto the

grid just take for instance what's

happening

or Nia at the period in which solar

panels have come down in price very

significantly same with wind we've seen

our electricity prices go up five times

more than the rest of the country and

it's not unique to us you can see the

same phenomenon happened in Germany

which is really the world's leader in

solar wind and other renewable

technologies their prices increased 50

percent during their big renewable

energy push now you might think well

dealing with climate change is just

going to require that we all pay more

for energy that's what I used to think

but consider the case of France France

actually gets twice as much of its

electricity from clean zero emission

sources than does Germany and yet France

pays half as much almost half as much

for its electricity how can that be well

you might have already anticipated the

answer France gets most of its

electricity from nuclear power

about 75% in total and nuclear just ends

up being a lot more reliable generating

power 24 hours a day seven days a week

for about 90% of the year we see this

phenomenon show up at a global level so

for example there's been a natural

experiment over the last 40 years even

more than that or in terms of the

deployment of nuclear and the deployment

of solar you can see that at a little

bit higher cost we got about half as

much electricity from solar and wind

than we did from nuclear well what does

all this mean for going forward I think

one of the most significant findings to

date is this one had Germany spent five

hundred eighty billion dollars on

nuclear instead of renewables it would

already be getting a hundred percent of

its end of its electricity from clean

energy sources and all of its

transportation energy now I think you

might be wondering and it's quite

reasonable to ask is nuclear power safe

and what do you do with the waste well

those are very reasonable questions

turns out that there's been scientific

studies on this going over 40 years this

is just the most recent study that was

done by the prestigious British Medical

Journal Lancet finds that nuclear power

is the safest it's easy to understand

why according to the World Health

Organization about 7 million people die

annually from air pollution and nuclear

plants don't emit that as a result the

climate scientist James Hansen looked at

and he calculated that nuclear power has

already saved almost two million lives

to date it turns out that even wind

energy is more deadly than nuclear this

is a photograph taken of two maintenance

workers in the Netherlands

shortly before one of them fell to his

death to avoid the fire and the other

one was engulfed in flames

now what about environmental impact well

I think a really easy way to think about

it is that uranium fuel which is what we

use to power nuclear plants is just

really energy dense about his mouth

about the same amount of uranium as this

is this Rubik's Cube can power all of

the energy that you need in your entire

life

as a consequence you just don't need

that much land in order to produce a

significant amount of electricity here

you can compare the solar farm I just

described Ivanpah to California's last

nuclear plant Diablo Canyon it takes 450

times more land to generate the same

amount of electricity as it does from

nuclear you would need 17 more solar

farms like Ivanpah in order to generate

the same output as Diablo Canyon and of

course it would then be unreliable well

what about the mining and the waste and

the material throughput well this has

been studied pretty closely as well and

it just turns out that solar panels

require 17 times more materials than

nuclear plants do in the form of cement

glass concrete steel and that includes

all the fuel used for those nuclear

plants the consequence is that what

comes out at the end since its material

throughput is just not a lot of waste

from nuclear all of the waste from the

Swiss nuclear program fits into this

room nuclear waste is actually the only

waste from electricity production

that's safely contained and internalized

every other way of making electricity

emits that waste into the natural

environment either as pollution or as

material waste we tend to think of solar

panels as clean but the truth is is that

there is no plan to deal with solar

panels at the end of their 20 or 25 year

life a lot of experts are actually very

concerned that solar panels are just

going to be shipped to poor countries in

Africa or Asia with the rest of our

electronic way

stream to be disassembled often exposing

people to really high levels of toxic of

toxic elements including lead cadmium

and chromium elements that because their

elements their toxicity never declines

over time I think we have an intuitive

sense that nuclear is a really powerful

strong energy source and that sunlight

is really dilute and diffuse and weak

which is why you have to spread solar

collectors or wind collectors over such

a large amount of land maybe that's why

nobody was surprised when in the recent

science-fiction remake of Blade Runner

the film opens a very dark dystopian

scene where California's deserts have

been entirely paved with solar farms all

of which I think raises a really

uncomfortable question in the effort to

try to save the climate are we

destroying the environment well the

interesting thing is that over the last

several hundred years human beings have

actually been trying to move away from

what you would consider matter dense

fuels towards energy dense ones that

means really from wood and dung towards

coal oil natural gas uranium this is a

phenomenon that's been going on for a

long time poor countries around the

world are in the process still of moving

away from wood and dung as their primary

energies and for the most part this is a

positive thing as you stop using wood as

your major source of fuel it allows the

forests to grow back and the wildlife to

return as you stop burning wood in your

home you don't you no longer need to

breathe that toxic smoke and as you go

from coal to natural gas and uranium is

your main sources of energy it holds out

the possibility of basically eliminating

air pollution altogether there's just

this problem with nuclear well it's been

pretty popular to move from dirtier to

cleaner energy sources from energy

diffuse to energy dense sources nuclear

is just really unpopular for a bunch of

historical reasons and as a consequence

in the past I and I think a lot of

others have sort of said well in order

to deal with climate change we're just

going to need all the different kinds of

clean energy that we have the problem is

is that just turns out not to be true

you remember I discussed France a little

bit ago France

gets most of its electricity from

nuclear if France were to try to

significantly scale up solar and wind it

would also have to significantly reduce

how much electricity it gets from

nuclear that's because in order to

handle the huge variability of solar and

wind on the grid they would need to burn

more natural gas think of it this way

it's just really hard to ramp up and

down a nuclear plant whereas I think

we're all pretty familiar with turning

the natural gas up and down on our stove

a similar process works in managing the

grid of course goes without saying that

oil and gas companies understand this

pretty well which is why we've seen them

invest millions of dollars in recent

years in promoting solar and wind this

just raises I think another challenging

question which is that in places that

are using a lot of nuclear have grids

that are mostly nuclear and hydro going

towards solar and wind and other

renewables would actually increase

carbon emissions I think a better

alternative is just to tell the truth

and that's what a number of scientists

have been doing I mentioned earlier that

hundreds of thousands of birds are

killed every year by wind turbines but I

didn't mention is that a million bats at

a minimum are killed every year by wind

the consequence has been that bad

scientists have been speaking out about

this this particular bat species the

hoary bat which is a migratory bat

species is literally at risk of going

extinct right now because of the

significant expansion of wind it's not

just wind it's also on solar the

scientists who were involved in creating

the Ivanpah solar farm who involved in

clearing that land have been speaking

out one of them wrote everybody knows

that translocation of desert tortoises

doesn't work when you're walking in

front of a bulldozer or crying and

moving animals and cacti out of the way

it's hard to think that the project is a

good idea and now we can see these

phenomena at work at an international

level in my home state of California

we've been stuffing a lot of natural gas

into the side of a mountain in order to

handle all that intermittent solar and

wind

it's sprung a leak it was equivalent to

putting 500,000 cars on the road and

currently in Germany there's protesters

trying to block a new coal mining

project

that would involve destroying the

ancient Han back forest in order to get

to the coal underneath all in an effort

to phase out nuclear and expand solar

and wind the good news is is that I

think that people still care about

nature enough for these facts to matter

we saw last year in South Korea a

citizen's jury deliberated for several

months weighing these different issues

they had to decide whether they were

going to phase out nuclear or keep it

and expanded they started out 40 percent

in favor of expanding nuclear but after

several months and considering these

issues they ended up voting 60 percent

to expand nuclear a similar phenomena

just happened last week in Arizona the

voters had a ballot initiative that to

vote on whether or not to continue with

nuclear or to phase it out and try to

replace it with natural gas and solar

they ended up rejecting at 70 to 30 and

even here in Europe we saw the

Netherlands is that one of the first

countries in recent memory to actually

announce as they did last week that

they're going to start to they're gonna

start to increase their reliance on

nuclear power in recognition that

there's just no way they could generate

significant amounts of energy enough

from solar and wind to meet their

climate targets I think it's natural

that those of us that became very

concerned about climate change such a

big environmental issue would gravitate

towards really romantic solutions like

harmonizing human civilization with the

natural world using renewable energies

but I think it's also understandable

that as the facts have come in that many

of us have started to question our prior

beliefs and change our minds for me the

question now is now that we know that

renewables can't save the planet are we

going to keep letting them destroy it

thank you very much