Cities are driving climate change. Here's how they can fix it

- What would the world look like

if extreme climate change becomes reality?

Well, here's just one example.

If temperatures were to rise
by three more degrees Celsius,

Shanghai, a city of 24
million people in China

will be wiped off the map.

And it's not just the only coastal city,

that's at risk of disappearing
beneath rising sea levels.

Globally 2019 was the second
hottest year on record.

Cities all throughout the world,

experienced record setting
summer temperatures.

In June, 2019, temperatures
in Churu, India,

exceeded 120 degrees Fahrenheit,

to the point that the
government warned citizens

to avoid drinking coffee, tea, and alcohol

at a fear of overheating.

Heat waves are becoming more severe

and come in place due to climate change.

Projected to lead to
deaths at the same rate

as all infectious diseases combined.

This map here, shows the
increase in the severity

and prevalence of heat
waves if the world follows

a moderate warming scenario.

By 2050, summertime highs
of 95 degrees Fahrenheit,

or 35 degrees Celsius,
will become the new normal,

in nearly 1000 cities
triple the number of cities

that currently experience
these sweltering temperatures.

But the irony is that
cities are not just affected

by climate change,
they're also causing it.

Cities consume between 60 and
80% of global energy resources

and account for approximately 70%

of global carbon dioxide emissions.

As we can see here in this map,

the light blue and the yellow areas

correspond to those with the highest

fossil fuel based carbon
dioxide emissions,

and also correspond to
major urban centers.

Aside from cities energy
consumption, growing urban areas,

convert the planets green surfaces

to buildings and pavement,
and these can absorb

more of the sun's energy,

than the natural grasslands and forests

that they've replaced,
making urban areas hotter

than their surrounding environments.

This phenomenon is called
the urban heat island effect.

Here in Singapore, downtown neighborhoods

can be as much as seven degrees Celsius

or 13 degrees Fahrenheit hotter,

than the rain forests that were once here.

While it's true that
cities are contributing

to climate change, they're also key actors

in forging low carbon emission pathways.

In dense cities like New York
city and Tokyo for instance,

the average resident is responsible

for over two tons of carbon
dioxide emissions per capita.

This is less than a
single passenger car emits

in a single year in the United States.

Cities around the world are stepping up

to tackle climate change,
with ambitious policies

that often exceed the requirements
of national governments.

Take Copenhagen for example,

it's committed to become
carbon neutral by 2025

and Glasgow in Scotland also plans

to become carbon neutral by 2030.

Today, there are more than 10,000 cities

all around the world, that are committing

to their own ambitious climate actions,

plans that include
emissions reduction targets,

clean energy and sustainable
transit projects,

and also energy efficiency policies,

that can save people and cities,

money, energy, and emissions.

Recent analysis shows
there's just 6,000 cities

combined with regions and companies,

are undertaking climate initiatives

that can reduce global emissions

by up to two gigatons of carbon
dioxide equivalent in 2030.

That's roughly 4% of the
world's total annual emissions

on top of what national
governments have pledged.

And this is just the start,
imagine what could happen

if 20,000 cities were to band together

to curb climate change.

While this potential for
city's climate action

sounds really promising,
cities must work to make sure

that these policies are
implemented fairly and equitably.

Where you live in a city,
your income, your race,

research is showing that
these factors can determine

your access to environmental benefits

like green space and sustainable transit,

and they can also determine your share

of environmental burdens
like air pollution

and climate change.

We observe these neighborhood
level disparities,

particularly clearly, in
the side-by-side images

of Los Angeles, comparing
income on the left,

and tree cover on the right.

The darkest green neighborhood
has an average annual income

of over a hundred thousand
U.S. dollars per person.

And over 70% of it has tree cover.

The blue neighborhoods
towards the bottom of the map,

only have a third of the income per person

and less than 5% tree
cover, 70% versus five.

This disparity has real consequences.

Green spaces are often public spaces,

and they're known to be associated

with social and economic wellbeing.

They can also reduce crime
and foster social cohesion.

Trees also can help to
filter harmful air pollution

and provide evaporative cooling and shade

and relief for some of
these high temperatures.

So not only are those poor neighborhoods

at a greater disadvantage
from access to green space,

but they're also more
vulnerable to air pollution

and climate change.

We can observe particularly
pronounced disparities

and urban heat according to race.

Our latest research shows that 97%

of major urban areas in the United States,

are exposing black populations
and people of color,

to a full degree Celsius
higher of urban heat

than their white counterparts.

Take a look at this map of my hometown

of Greenville, South Carolina,
unlike the name suggests

it is not green for everyone.

The hottest areas of the
county shown on the map in red

correspond with the highest percentages

of black and poor populations.

And we're seeing similar
patterns throughout cities,

all across the United States.

To address these inequalities,

cities are starting to
strategize and develop plans,

that can ensure that climate benefits

are provided to all of
their citizens equally.

Take Bogota, the capital
city of Columbia for example,

it has one of the most
extensive bike networks

in all of Latin America,
connecting people to jobs,

education centers, and
recreational opportunities.

A new bike highway project can allow

for around 42,000 daily bicycle
trips, and potentially avoid

270,000 tons of greenhouse gas emissions.

In Africa, where many cities

lack universal access to electricity,

many grids are providing
approximately 73 million households

with clean electricity.

So as we can see from these examples,

tackling climate change
has to start in cities.

Many cities are starting
to flip the script

on climate change, proving
to be part of the solution

and not just the problem.

And bringing the kind of
innovative solutions that we need

for a more just and
sustainable world, thank you.