Transcript Climate change

Climate change,
Does it matter?
Martin Hedberg meteorologist
Swedish Weather Center
Weather (Precipitation, clouds, winds, humidity, temperature…)
Natures way of balancing forces in the atmosphere.
Climate
Climate: 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
Energy radiates from
the atmosphere
Radiation from the
sun warms the
earth’s surface
Greenhouse gases are
being warmed by the
radiation from earth
Without
With
greenhouse gases:
+15
-18 degrees!
degrees!
- Climate change External causes
 Solar activity
 Earths orbit
 Meteorites
Internal causes
Natural
Internal causes
Anthropogenic
 Feedback
 Emissions of greenhouse gases
 Volcanic eruption
 Particles/clouds
Chance
 Land change
Greenhouse
gases
(has a warming effect)
Left in the atmosphere
for 100 years
Particles
(mostly a cooling effect)
Left in the atmosphere
for 1 week
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.
Carbon dioxide is used to describe
how we affect the climate
 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
Climate change within 100 years:
About half an ice age, but on the
warm side
Year 2100?
Year 2000
Year 1900
Ice age
Temperature as a tool to measure climate change
 Easy to make statistics
from
 Easy to compare to historical
 Might misunderstand
climate change
”climate-temperature” vs. daily temperature
 Climate change is also precipitation,
humidity, winds etc
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.
Humanity's large self-deception
”It’s just natural climate change”
”When we understand all the physics, we can stop it”
”Somebody else has to lower their emissions”
Many small steps. They all add up.
 More effective use of energy
 Renewable energy
 Capture carbon dioxide
from both bio-fuels and fossil fuels
Average temperature rises
More/heavier precipitation
Flooding, landslides…
Weather patterns change
When, where, how often, strength…
More evaporation.
Drought, erosion, wildfires…
Climate has…
Long braking distance
Climate has…
Domino effects
Climate has…
Many irreversible processes
YES
Climate change
matters.
As usual.