Climate change, Does it matter?

Martin Hedberg meteorologistSwedish Weather Center

Weather (Precipitation, clouds, winds, humidity, temperature…)

Natures way of balancing forces in the atmosphere.

ClimateClimate: Statistics about the weather.

Climate is the average weather pattern over a longer period of time.

100 years

Climate change (Weather patterns, glaciers, sea level rise…)

Climate change is a significant change in weather patterns.

When you put it in the perspective of a longer period of time you find it has

happened many times before.

100 000 years

Greenhouse effect

At any planet with an atmosphere.

Energy radiates from the earth surface

Radiation from the sun warms the earth’s surface

Without greenhouse gases:

-18 degrees!

With greenhouse gases:

+15 degrees!

Greenhouse gases are being warmed by the radiation from earth

Energy radiates from the atmosphere

External causes Solar activity

Earths orbit

Meteorites

Internal causesAnthropogenic

Emissions of greenhouse gases

Particles/clouds

Land change

Internal causesNatural

Feedback

Volcanic eruption

Chance

- Climate change -

Greenhousegases

Particles

Left in the atmosphere

for 1 week

Left in the atmosphere

for 100 years

(mostly a cooling effect)

(has a warming effect)

Roger Revelle and Hans E. Suess. Carbon Dioxide Exchange Between Atmosphere and Ocean and the Question of an increase of Atmospheric CO2 during the Past Decades. Tellus 1957.

CO2

Easy to make statistics from

Easy to compare to historical climate

There are more greenhouse gases, both natural and anthropogenic

There are more things than greenhouse gases that affect the climate

Carbon dioxide is used to describe

how we affect the climate

Ice age

Year 1900

Year 2100?

Year 2000

Climate change within 100 years:

About half an ice age, but on the warm side

Easy to make statistics from

Easy to compare to historical climate change

Might misunderstand ”climate-temperature” vs. daily temperature

Climate change is also precipitation, humidity, winds etc

Temperature as a tool to measure climate change

The thermometer is how we measure climate change

But it isn’t about the temperature itself.

It is all about the consequences.

Ideström & Skinnarmo

It’s getting warmer.

More evaporation. And more rain.

Sea-levels are rising, Glaciers are melting, Extreme

weather...

Plants and animals adapt, or disappear.

People and societies adapt.

”It’s just natural climate change”

”When we understand all the physics, we can stop it”

”Somebody else has to lower their emissions”

Humanity's large self-deception

Many small steps. They all add up.

More effective use of energy

Renewable energy

Capture carbon dioxidefrom both bio-fuels and fossil fuels

Weather patterns changeWhen, where, how often, strength…

Average temperature rises

More/heavier precipitationFlooding, landslides…

More evaporation. Drought, erosion, wildfires…

Long braking distance

Climate has…

Domino effectsClimate has…

Many irreversible processesClimate has…

YES Climate change matters.

As usual.