Thank you.

Now this is this is going to be more
structured a kind of discussion.

Maybe a direct talk so
I encourage you to put up your hand.

I'm happy to stop and explain things and
ideas presented here on themselves and

so it's a good idea to stop me when I have
confused you which I'm sure to do and

I'll ask him to take a sip
of water which is great.

So we're going to talk
about general topics today

the mechanisms of climate change and
I'm assuming in this day and

age that most people are reasonably
familiar with the greenhouse effect we're

going to talk about how it works but we're
not going to spend a lot of time on it but

there are two distinct mechanisms that are
driving the phenomenon of global warming

one is an atmospheric mechanism
which is the greenhouse effect and

the other is a surface mechanism which is
driven by the surface changes over time.

Which is and we particularly see in cities
and that's going to be my principal

focus today view of the greenhouse
effect and global warming.

What's driving that urban warming trends
in large US cities which is what my study

is focused on that I'm going to
present today the principal study and

then we'll talk about the threats of
urban warming to urban populations and

it's specifically what planners can do
about it in planners and urban planner but

there are lots of folks who think about
and plenty for human health and cities and

so when I say plenty in
the broadest possible sense.

I like to start my climate talks with this
particular slide this is a page taken

from Popular Mechanics and one nine
hundred fifty three and I'm highlighting

this article here growing blanket of
carbon dioxide raises temperature.

I like to start with this for two reasons
one job of showing how pressing it with

science was the greenhouse
effect many many years ago.

This is more than fifty years ago.

Very clear picture of what was happening
with the accumulation of carbon dioxide

in the atmosphere and

how that was when the earth a pretty
good projection out to Twenty eighth.

Of what temperatures would look like
suggest about a three percent increase in

average temperatures.

That's looking like a little bit to what
we think we're going to see now by two

thousand and eighty but it's still
a fairly good estimate and it suggests two

things One is that we've had a good idea
of the science of global warming for

a long time and we haven't done much
about it in the intervening time

that I also like about this is that
it's found on page one hundred one.

And it's next to the cloud on his tiny
bike and I think this is for a long time.

How the issue of climate change has been
treated particularly in this country

as kind of a climatological curiosity
something that we've known about

seven minute few people been concerned
about but not really front page news.

Until recently.

This is no longer the case and
really just in the last few years and

I think since to a significant
degree we have Al Gore to thank for

that I think has really is awaken
people's understanding of this issue but

what I would argue is that today
the issue of climate change

the urban heat island effect this urban
mechanism they're going to talk about

is still largely viewed as
a climatological curiosity and

what I'll be argued today is that it is
dressed as threatening to us for those of

us who live in cities and so we need to be
very much aware of it and planning for it.

This temperature trend is something
that everybody has probably seen every

year we have an announcement that
last year was the warmest year

on record of one of the ten hottest years
on record and the data are developed by

NASA Goddard Institute for Space Studies a
number of groups globally who do this for

measuring global planetary
temperatures but NASA is one of them.

And this is their particular data set for
the continental US and

they're showing this trend that is
characteristic that we see today where

we have up and down in terms of the year.

In the last twenty or so
years who struck this bike and so

that's that's the information
that is most commonly

recognized as what's going on now
in terms of climate change and

we want to talk about today how they're
measuring this briefly what is the theory

of the mechanisms that are driving
this warming effect over time.

This is one of my favorite slides
of the greenhouse effect today but

I think just as a good job of capturing
these two mechanisms the atmospheric in

the surface mechanism which showed years
we had this accumulation of greenhouse

gases carbon dioxide is one of those
prevalent it's what we hear about but

there are others as well water vapor
is a very powerful greenhouse gas.

Although it's not one that we directly.

These greenhouse gases are building
up in the atmosphere and

they're trapping outgoing
wave radiation and

so we have two basic classes of
radiation that we talk about but

that mysterious system radiation
comes down from the sun and

the atmosphere the greenhouse gases
are largely transparent to the visible

radiation for the most part it
passes through the greenhouse gases.

It's absorbed in the or surface to
surface and in that process the radiation

is readmitted as a radiation and so its
physical properties have changed somewhat.

It's really here and

that is absorbed by these greenhouse
constituents these greenhouse gases.

So the short passes through that

tract absorbed in that creates
what we call this radiated

Firstly the atmosphere in the surface and
it drives temperatures.

That's a good thing if we did not
have that kind of greenhouse gases

the planet wouldn't be very hospitable for
life today.

And so having the natural greenhouse
effect is a good thing and

nobody disputes that.

What's been debated in recent years is
the degree to which are intensified

the accumulation of greenhouse gases
in temperatures and other effects.

See with this.

That's the atmosphere and there's also
a surface part of this equation and

again this red line that's absorption
in the degree to which this is a good

surface changes displacing
natural vegetation for

agriculture and also for cities when
we cut down trees in the context of

the capacity of the surface to
absorb incoming solar radiation.

That is and they may actually reflect away
without contributing to the fact most

of our Lancers activities are increasing
the absorption energy of radiation.

And so the atmosphere process surface
process temperature at the global level

compared to a pot of water we can think of
the greenhouse gases as the accumulated

across the pot of boiling water and
as we slide the litter cross and

we track the temperature within
the pot of boiling water.

We can also turn up the burner and
that's what we've been doing surfaces

that we can raise temperatures completely
independent cumulation greenhouse gases.

So with these two independent

phenomena that are driving the cumulation
of temperatures in the atmosphere.

We probably see this particular phenomenon

presented to us in terms of the
accumulation of greenhouse gases is this

atmosphere to fact if we look at
a scale of ten thousand years.

It becomes rather dramatic and apparent.

Cumulation of carbon dioxide
in this case carbon dioxide.

So there's the atmosphere
component driven by

many things the surface
component which we can.

In many different contexts.

The first pictures were displaced.

By the trees in this place and
that with crops we actually

increased temperatures that drives this
phenomenon also the burning of the forest

creates a lot of carbon dioxide which
contributes to the atmospheric phenomena.

Places like displacing forest with
subdivisions and urbanization

increases surface temperatures
raises the drives this phenomenon.

One question that's important.

That is not invested in
sufficient detail is the relative

contribution of these two mechanisms
the atmospheric versus the surface and

one of the few to look at this trying to
measure the contribution of the surface

change the temperature change over time
and the cumulation of greenhouse gases and

what they find this is a approach in
which they're measuring temperature

at the surface and then using weather
balloons to measure it higher up in

the atmosphere to the surface changes and
they're looking at

the differences between temperatures and
how they're changing over time.

But they conclude it is portions of
the U.S. where we have stations and

we can measure temperature surface
phenomena it's responsible for

fifty percent of the increase in
temperature is that we've seen greenhouse

gases is responsible for about fifty
percent raise an increase in temperature

we've seen based on this one study
looking at the US And there's a need for

this if this is true equally

as important the atmosphere is focusing
exclusively on greenhouse gases.

There is very little tension in
the scientific literature surface

changes in awareness of this.

In the case of the surface changes
which impacts really a small.

Percentage of the surface of
the earth cities account for

five percent of the surface of the earth
but they account for the majority of

the human population now for the majority
of greenhouse gas emissions so

urban areas are small percentage of
the planet but a very important region

in terms of how they're contributing to
climate change and within the urban areas

we have this phenomenon known as the urban
heat island effect which is manifested

through higher temperatures in cities and
most of us have probably experienced this.

If you have a temperature gauge
in your car and you drive out.

Outside the city.

You will see the temperature fall most
likely the city number of studies ever

number of cities have found its effect
average between six degrees Celsius and

ten degrees Fahrenheit.

So that's significant on a hot summer
day it's not unusual to see an eight

to ten degree Fahrenheit
difference between.

And about fifty miles outside the city
that's significant temperature

difference it's equivalent to what we
expect to see through one hundred years of

atmospheric greenhouse effect
projections in this range about.

We've already experienced one hundred

years of the temperatures
we're experiencing today.

And of course that's happening on top of
what's happening at the planetary level

this phenomena is driven by principle

mechanisms first is the displacement
of natural vegetation trees and

natural mechanism through
the joint processing to

evaporation transpiration evaporation as
well as a phase change into water vapor.

That absorbs incoming solar energy that
absorbs the energy within the water itself

evaporate water vapor in the water
vapor actually carries that energy

content loft into
the atmosphere doing that sort.

Energy from the surface will
contribute to a rise in temperature and

served to surface because.

What we call sensible temperature.

It creates a shift from the sense
of the way to describe it but

essentially it's a natural mechanism.

Transpiration Is this similar
process happens with the systems and

the water process itself it is

the solar energy to essentially
drive that phase change.

So true in other vegetation and natural
mechanisms for cities and that's lost.

So if we're going to increase
temperatures for that reason

we may also increase temperatures
because we're changing the surface.

And so if we put down
a black asphalt parking lot.

We're going to increase
temperatures because it's absorbed

into that as as it absorbs
that radiation radiation and

that contributes to temperature
again that we can feel.

This is a picture of responsible.

Design techniques that provide natural.

Away a lot of the sunlight that away.

It's not absorbed.

It's not driving temperature
again America in general in

North America we often use Dark Materials
particularly the East Coast and

this is a part of the Northern European.

Black.

Makes very little sense to do that in
a place like Atlanta that's largely

been a lot of the summer
that we have to offset.

Simply because we.

Same with asphalt.

Writer.

Concrete.

Does a good job of this radiation.

A lot of this is driven by preference and

it's certainly driven by
the design about urban areas.

That's the second piece of the first
one is transpiration the second.

One is needed missions and so
whenever we can bust in a power plant

a lot of heat the stack when we drive our
cars there's a lot of heat that comes out.

When we run our air conditioning systems
we are mechanically removing heat from

inside or outside and
that contributes it's a small or

smaller factor that directly contribute
to elevated temperatures in cities and

so these three cities
are driving this urban heat.

Which is.

In this range and that creates particular
problems in cities when we think about

climate change particularly if the planet
as a whole is how rapidly our cities.

Again this is where most of us live.

And we have to plan temperature change
over time and so we need to think

about this specifically with the urban
context questions about this

because it's such a small
percentage is significant for

people because it's just about five
percent of the land surface and

there haven't really been
studies that have tried to

drive the planetary temperature
change themselves to be a very small

percentage because it's just such a small
percentage of the earth's surface.

So it's a great question.

It's a significant issue if you
live in cells are not directly

driving the temperature change near
you but they are indirectly driving

it through the emissions of greenhouse
gases and so they're driving the.

Atmospheric process which is running the
globe as a whole but they're not driving

surface changes and if you don't
live in the city that makes sense.

I don't know it's a good
question here that we're losing

a couple state north of the area
every year and it was exaggerating.

I don't know the total probably five or
ten years ago but

I haven't looked at that issue.

It's a good question but it is rapidly.

Depleting and
we know ironically most recently it's

in part our own policies in terms of
biofuels and in this country biofuels

in the push to produce ethanol is shifting
crop production from Serbian the corn.

And while we grow corn in this country
which increases the demand and so farmers

in South America are plenty more soybean
in cutting down more forest to do that.

So it's a significant problem
I wish I knew the personally.

OK Also we can see with thermal
imagery that a very small

spaces are significant
differences in temperature.

This is showing in the early evening
that the driveway has retained a lot of

the heat but
during the day the grassy surface because

it has the mechanism of
evapotranspiration is much cooler and

it has not absorbed as much heat
during the day and doesn't retain it.

Also in the house in the attic
where the heat is rising.

You can see.

In the building accumulated in cities
particularly in downtown districts not

only are the building to be more heat and
it may be that as they readmit this

radiation really actually
I mean it's a trap and

that's happening between buildings and so
we have urban canyon geometries as ours

described downtown districts
that is a unique property.

So for this study.

I wanted to.

This question rapidly than
the planet as a whole and

the reason this is an important question
to the next is that observations

of planetary warming are based almost
entirely on weather stations and so.

We're going to between two and six degrees
they're talking about in areas that

average and that's important because what
they're trying to measure is the fact

if you measure temperature measuring both
the atmospheric phenomena phenomena and so

if you focus on the atmospheric phenomenon
you want to take temperature outside of

cities and so that's important to do but
it doesn't tell us much about what will

happen with this study is focused
on that what you see here is

from downtown marks and
this is showing the surface.

Clearly a very hot.

Place where again if you want to
talk about the plan as a whole you

probably don't want to
measure temperature but

if you want to think about how
temperature is changing in cities.

This is exactly where we need to be
focused on the temperature trace.

I showed earlier network stations and

this is a special network in this case
the global climatology network is based on

a series of first weather stations that
weather stations that are high quality

quality what I mean is they
are more common sources a bias

or is the word.

And if you're interested in looking at how
temperature has changed over the period of

decades and we really have to
look time periods if you want to

measure climate change because there
are so many short term climate.

Logical phenomena like a short term shift

they would need to look over
several decades to see a trend.

And so if you want to measure temperature
over several decades you have to find

weather stations that have been in place
in the same location for many decades.

So a change in location of the instrument
if we were to this weather station and

the elevation change that would change
the temperature record independent of any

climate change is just because you changed
elevation in higher elevations or colder.

And so that needs to be corrected for

when the temperature record
change in instrumentation.

If it's some point in time we
are monitoring we have a more sensible

monitor that can cause a change
in the temperature record that is

not a problem of climate change as
a product of the instrumentation.

So I can control for that with
a control for the time of observation

if you're measuring temperature have
a different trend and if you measure it.

That's a control for and
then finally number for contamination and

that's that's the work contamination by
urbanization that if you have weather

stations that are located in cities
then we need to statistically adjust

the temperature trend to account for
the fact that it's an urban area.

This is precisely the way we're
measuring temperature change on average

I mean I want to measure
the extent of contamination.

I want to measure exactly how
much temperature is being driven

by what's happening.

And that's what's different about.

The other studies that preceded it.

So I've acquired temperature data
between one thousand nine hundred fifty

in the year two thousand and fifty at the
sixteen most populous metro regions us.

In this case and this shows the cities
that are included shows their populations

and looking at these regions.

It's a regional population not just
the city but the metropolitan region.

Populations are about
seven hundred thousand.

Greater than five minutes
that are missing that

are largely like Chicago Chicago does
not have a single weather station

with a consistent temperature record back
to nine hundred fifty and so the airport.

The temperature record was compromised so

Chicago could not be included in
the city San Francisco same story.

So these are fifty of the sixty

which I could get high quality
temperature back to nine hundred fifty.

This is more than half of the U.S.
population metropolitan areas and

again I'm trying to get a sense of how
temperature is changing where we live.

This is what I'm getting for each station.

This is NASA.

This is the same data set that they use to
measure planetary change year after year.

I'm just cherry picking it
to look at the large cities

in the watch their temperature trends.

So this is from Hartsfield Jackson Airport
this is the temperature trend there it

goes back to eighteen.

So that's a long time for
sure and I'm back to fifty again.

And what we see here is
actually characteristic of

most of these in your logical stations
is that temperature is increasing and

rather dramatically in the fifty's and
sixty's and.

Has been increasing
rapidly this temperature

is driven by a phenomenon known
as the Pacific oscillation or

at least in part by that which is
happening over the Pacific Ocean and

you can think of it as a long term cycle.

And so when that when
the Pacific Decadal Oscillation that

goes into a negative phase we have a cool.

Temperatures in the ocean and that creates
colder conditions across the continental

U.S. It's a very significant effect.

It's a long term phenomenon so
it happened over decades and

this is one of the reasons why there's
been a lot of the debate about whether

climate change is actually being
enhanced by human activities.

There are lots of him.

It's fairly common phenomena but our
driving temperature change over a decade.

Temperature record to really
measure these things looking for

nine hundred fifty thousand
is right there on average.

We've experienced other stations and so
I have one of these temperature traces for

every one of the cities have
a station within the city and

then three for
other stations outside of the city and

I talk about how those
were selected right here.

So what you see here is an image
nightlights you may have seen this before.

Looks like from space at night
just illumination of cities and

this provides useful information
to an urban areas and

so I had other stations that are within
the urban fabric and weather stations that

are free contamination that are outside
we can do that with population

for a thousand square kilometer

as a basis between an urban we can use
that but it's not always reliable and

that you could have close to a military
installation there as a runway and

it could have higher temperatures that you
would normally find in a real area and so

what I'm trying to do here is use
the station selection as a process and.

Fifty urban weather stations and

one hundred fifty weather stations around
each metro area that I can use to measure

the difference between urban
trend trends over time.

So the urban station in our case is the
airport usually cities only have a single

first weather station back to
nine hundred fifty in this case.

So there are lots of weather stations but
typically don't go back far enough to

be steady or they suffer from some source
of bias in the temperature record and

so that creates a problem for
the airports and I'll talk about that but

I'm limited to one station the best way
to do this study would be to have a net.

Stations across every city.

We don't have that station and
that creates a problem.

Fabric itself.

One hundred fifty kilometers of
the urban population they have.

But they're just not suggesting that area.

So this is

this is the airport station is
just west of the airport and

this is the case with all airports and

other stations are trying
to measure their monitors.

And they are trying to
get a sense of self.

Challenge with this is not of
course the best question to ask

that are similar to cities
they have lots of concrete.

So many ways in terms of the cities but
they're not located.

They found right downtown.

Pictures.

From the.

From the surrogate if we're going to have.

This is about as good as you can do.

Could have a station right downtown.

Given that we don't have those
measuring temperature as well.

On average under estimating
temperatures that we find downtown and

that's because we don't have that effect.

That's creating the trapping everything
that we would find in an urban district.

Very few true but
we don't have the trap heat and

actually look at the distribution
of surface temperatures the central

around the airport

on average it's amazing
the temperatures that we see

this is what we found.

As a temperature record.

It's a conservative measure that

would be higher than what we would
see downtown questions about this.

OK.

So this next few maps and
the results of the data that I

gathered this is showing the trends
again the station cities

showing the urban temperatures the same
we're looking at five decades of

temperature change and on average across
the great how much is temperature change.

In this case the average
across the urban per decade.

Pattern to continue five decades

change so
on average since one nine hundred fifty.

Airport.

Weather stations have experienced
an increase in temperature degree Celsius.

And there's lots of distribution
here in terms of in some cases most.

Pittsburgh.

Actually the trade we're seeing here

is that there have been periods of

this period of particularly Pittsburgh.

On average recent decades fifty
years the predominant trend.

That's because we had exaggerated

recently.

That's driven by some sort of specific

reasons for that not something
that I'm interested in but

it's enough to say that fifty cities.

So that the urban trend
similar weather station.

They're experiencing a predominant factor

here is the South actually experienced.

During this period of time on average
there was an increase in temperature.

On the for.
I don't combine the two

we're looking at the Urban Heat.

And that is the difference between
the temperature trend in the first

case we saw the average the average
point one five point five.

This is what the Urban Heat were
subtracted to take to be represented.

That's happened in the background.

Tracking that for a fact.

On average of five degree
Celsius per decade.

OK OK So let's talk about where some
indications of this are important

places that are necessarily
places where usually

stations faster than
urban weather stations.

So what this means is that the urban
weather station is over time

to start with has a lower
temperature on average but

the difference between the two
which is the different temperature.

Here.

That's the case here the other way.

Philadelphia Washington the urban

stations faster than
urban trend confusing.

Trends here in terms of
the South very consistently.

Shrinking here for the most part but

they're shrinking also is a question
that I have an interest in this.

I had some theories on why that very
complex question in the case of the north.

Is that rapidly during
this period time most of

the population in
the southeast vapidly and

trees and things are pretty clear and
in the northeast.

You might have been happening have
a slowdown in economic development where

the cities are actually
generating constant and

that is serving to slow down the rate
of increase if the rate of increase in

temperature in the urban areas has
slowed down to start to catch up and

it creates a trend.

I

don't know if it's the Beltway per se.

I think in many cases you have.

But it's really population growth and
economic development growth and so

we've expanded because we have
lots of population growth and

lots of it could be a range of factors but

that could be one factor that's driving
this and other possible reasons that

we have the power plants that are found
right downtown which we don't see as much

in recently developed cities and so
that's creating a high concentration of.

There could be a lot of
things that are driving this.

It's not my central
question is the average.

The average the average
trend is twenty and.

Over time.

So let's look at the result of how

I want to translate this into
actual different estimates

based on different stations.

OK.

So my subset of stations in the same

smaller number of stations within
the US and what I would like to show

is so.

Stations across.

So if

one hundred point.

So the difference here is.

A subset of stations the last two percent.

Read that sixty percent of

it's more than half have
a positive trend over time.

That's a significant trend.

To change as a whole.

That we have this atmosphere of fact

across the entire planet
across the entire planet.

That's what's happening in
the background trend in cities

we superimposed on the effect
because of greenhouse gases with.

That background.

How much

longer time period in the first
half of the twentieth century

in the second half of
the century is the gallows

the same temperature.

Areas urban areas or sizes to.

Probably the difference between.

It's probably the size of the.

Fact that they use a very different
methodology that I did and

then finally my study which is
the only one which is a city area

twenty five degrees a half
per cent per century.

That's how much doesn't sound like a lot.

OK so
these findings on average the decade.

Never fear.
This is this is just the.

Thirty percent greater
than that approximate

taken to represent the background
kind of planning for

cities in which the effect
intensified those red dots sixty

one hundred fifty percent greater than
that approximate rural areas as well.

Missing areas developed by
the government panel on climate change

are based on background rates
scenarios and they're projecting.

Significantly underestimate the rate
of time these observations.

If we think about temperature change
within the cities we should assume

temperature of about five percent and

then have on top of the fact which
was found to be thirty percent

greater only one hundred fifty percent
greater depending on the class of sense.

We're looking at.

So let's think about this actually.

Government twenty

one hundred one point three percent.

Expect for
those studies on average to increase by

degrees Fahrenheit by twenty one hundred.

If you look at the subset of cities
where there is growing over time

two point five hundred fifty percent
by two point five and we get twenty

three new projections at

temperatures which is the high
end of the range increase in

temperature is twenty three average
temperatures today in the summer.

The average high is so

if we add twenty three degrees
continue all the way out there.

We're talking about average high
temperatures a bad one hundred

ten degrees and.

That is higher projection conclude

whether this will happen or
not is hard to say back mechanisms that.

Is that we will be increasing
between one thousand five

hundred two thousand are probably going
to run faster than they have in the past.

So this may underestimate the trend but
if it estimates it correctly.

This is a serious public health challenge.

It's a serious planning challenge
in cities that really isn't

being contemplated.

Today.

So many cities can induce rainfall

as we found recently very
little science to support that

rainfall event downwind of Atlanta.

You have a lot of energy that's
been put into the atmosphere and

that is driving down really and
we see that today.

If we created rainfall over
the actual urbanized district.

We could study and so as he increased.

I have a negative feedback that I don't
know if that will happen but it could and

it's worth mentioning.

And then again we don't know how
the weather phenomena play out.

This is the tracking recently but

there's this sense back
that the atmosphere.

Can track severe weather side but
a lot of these questions

are to that

extent near that extent we've got a very
serious public health problem in cities.

A little bit and talk about what we should
do about these problems within cities

the emphasis has been

in how we're going to reduce
greenhouse gas emissions over time.

And how to do that but
it's very important to know today.

Is going to have project for
many years and

that's because the atmospheric residence
time of carbon dioxide carbon dioxide is

very slow from the atmosphere for

about fifty years you still have about
fifty percent of what was there and

a lot of the carbon dioxide a significant
amount of carbon dioxide that was admitted

to this fear is still driving this and

other greenhouse gas emissions for
quite a while.

And so that means if you want to
cities are places where people say

ten to twenty years much for

you but we also need to think
about adapting to temperature.

That are already underway
right away to do that

when we think about the threats of climate
change some of the more exotic of facts

attention and measuring this is
happening now the extent to which

nobody knows but
there's a lot of focus on.

Catastrophic exotic effects such
as infectious disease significant.

Attention to the effects of
just increasing temperature

where the implications of the increase
in temperature temperature.

In two thousand and three on the high
end of the estimate estimate about fifty

thousand people died twenty to
twenty five thousand people died so

far twenty five thousand
people die within a few weeks

from the heat from high
temperatures Chicago

preparation for a refrigerated truck
outside the office to deal with the.

Very difficult situation to
deal with the effects of heat.

Particularly when you have brownouts with
loss of power energy gets hot outside.

And that's when the system is strained.

So we need to start thinking that for
heat.

Rather than

hurricanes per person here in

this period of time you add
all these up on average

the people who die every year
from heat waves on average there.

For sure.

I think about temperature and air quality
the range of effects and the range of

public health issues associated with
temperature we know temperature is

very closely correlated with
information and so I think it's hotter.

We can expect to have small base in
places like Atlanta is quite likely

climate change impacts in
infrastructure transportation and

this is a report that just recently came
out from the translation research minority

trying to get a sense of right are the
types of impacts we should plan for

I'm tired of thermal expansion
of bridges pavement integrity

when you get above ninety
degrees one hundred ten degrees.

You start to see rails streets
are a little broccoli and

this is happening today in terms
of two thousand and three.

Well systems shut down because of the
tracks where it got too hot or literally

two thousand six hundred
exceptionally explode in the roadway.

That's a significant structure
impact asphalt melting in cities

where do you do you get to
work when the road melts

buckles the range of
impacts from temperature so

if any of routine temperatures over
one hundred seven days in Atlanta.

A routine temperatures of one
hundred ten degrees in the summer.

We're going to see lots and lots of
infrastructure impacts the planners

certainly need to be
concerned about everybody and

think about where this is going to cost to
deal with this where the range of impacts.

Other infrastructure
are very energy to offset

our dependence on oil and other sources
of fossil fuel when it gets hot and

stagnant when they'll stop growing so
energy it may not be there for

you when it's hottest to take that into
account terms of planning for energy.

Consumption.

Now this is

quite significantly temperatures
ten percent increase in usage.

Just because it's hot water for

the existing uses when
temperature goes up packs.

So what do we do about this fact

in terms of missions.

That would allow us to.

Period of time around the country.

Seventy dollars per tree.

But a lot of it is driven by the city.

This is a very cost
effective strategy seventy

million dollars potential
reduction in air pollution.

This is one of the very
short period of time.

Service reflectivity increasing this is a

period of twenty years.

Place in our streets materials surface.

Increase in the reflectivity.

How effective might this be.

This is a study that was conducted
by folks at the Lawrence Berkeley.

Case in Los Angeles
temperatures by about one and

have to agree Celsius highly reflective
materials another three degree reduction.

Three degrees is within
the range of projections for

a fact and so you could
significantly if this is accurate.

You can significantly strategies.

Because you've said this is
going to impact the planet.

It's going to reduce the use of energy.

It's going to depend on where
you are in the country but

if you're in that part of
the country where Los Angeles.

If you can reduce greenhouse
gas emissions for sure.

May not be the case in point which is
depends on where you want to question

the questions.

To begin with a little bit but

what's most important here is that they
are providing actually coming into

the trade in five years.

I don't know but the other question.

OK so then also energy conservation.

Classics showing the relationship
between energy transportation.

Energy consumption things like

areas people drive they can take.

It's fairly well established.

Down to a smaller degree temperatures.

We're talking about retrofitting
strategies you can plant trees higher

reflective surface treatments in
the population over the next sixty years

fashion if you want to surf

the surface temperature district for
a long time.

Temperatures but we have to remember here

and that's essentially what this
study is trying to tease out.

We can pretty well compress
population growth into a higher.

Higher temperatures there are radical

energy to be atmosphere and
so in this case.

Now we're asking a simple
question how much additional

natural two different models
of development want to

hire the architecture and design.

The results of the study
suggests that as size increases.

The production tends to increase as well
and that's counterintuitive in some cases

when we first think about it a lot for
example for a single family residence.

Driveway driveway so
we have an increase in temperature.

We also have a large area in
this pattern here is increasing.

Obviously it's a lot size increases areas
increasing which unique about this dataset

which may be somewhat unique to Atlanta
but probably not that unique is that.

We have displaced a lot
of areas with lawn area.

So we have the experience of resident
are in town neighborhoods and

that is coming at the cost but used to
be there when we cut down trees and

establish a lawn we actually
increase the tree from the property

a lot better than driveways better
than street rooftops but the trees

in this process the flux of
energy to the areas with area.

So if we look at your
typical higher density urban

suburban we see production
on the suburban line.

So it's found to have
a positive association

and have a negative association found
to have the greatest effect on partial

variables here in this model
that we don't need to go into

is that the most significant
variable discover.

Approach as we develop is to
actually develop any higher because

it's been official to us

results of the study twenty five
percent reduction in the area.

For the average person proportion was
found to reduce emissions by about

thirteen percent.

Twenty five percent
reduction in the area and

previous cover was trying to
reduce emissions by sixty percent.

If we combined those to reduce emissions
by about twenty eight percent.

In the combination with an increase

from thirty five to sixty percent
missions by forty percent.

And so by changing our zoning regulations
our subdivision regulations to

restructure the design
of the house itself.

If we just reduced the size in reconfigure
things we could reduce emissions

substantially said the mission
of regulations could actually

cover and this was a quality issue but
this is a study based on Nansen Wisconsin

which is looking at exactly you could do
in terms of changing the configuration of

the frontage of the setback.

We have is that required
this house to be set back

a minimum distance from the street.

And as we push the house further back.

The driveway the longer.

This increases the absorption of feet and

development regulations are zoning codes
without any change to the house could

significantly impact on the environment
to improve these problems.

Than half of the built environment rather
than half of the built environment

in two thousand and five did not exist
in two thousand and twenty five.

I'm sorry this is.

Again the half of

the built environment we see in twenty
twenty five percent of the footprint

of cities over the next twenty five years
and that's an impressive statistic and

that a tremendous opportunity
to think about how much

we're developing the kind of materials
were we thinking about thinking

about this is a huge huge challenge for

us that's happening during our history.

The global climate change is
driven by the atmospheric.

The surface mechanisms they
are related but we have.

That's happening across
the planet as a whole.

Study of cities between one hundred fifty
and two thousand times the average rate of

one point three times greater than
the background planetary rate for

a subset of cities including
growing over time but

amplification raised two
point five times and

that's a significant warming which
could be very significant temperatures.

So you can offset the rate
of warming over the.

Natural tree canopy in
the case of Atlanta and

Hansen of surface reflectivity
through a resurfacing and

a reduction in energy consumption in
preservation of existing green space.

So the higher density of development
strategies is all about that last

point presume.

Existing green space at the poor
free of the urban area.

That is my last slide and I'm happy to
take questions you might have about that.

I know it's a lot but

I'm just trying to give you a bit of a
window on how the field of urban planning

can think about climate change how climate
change to cities and what we might do.

For work and this is this is based on
a paper that was published and if you want

a copy of that paper and direction to
the website I do have an e-mail on here.

Otherwise.

Thank you for coming for shit.