The evidence for climate change

1. This guy…is Jim Inhofe, senator
from Ohio
He is the Senate Environment Panel
Chairperson and he says climate change is
a hoax and that people who care about the
environment are going against the Bible.

5. Climate Change and Ozone
Depletion
Ch. 19

6. What do I need to know about
climate change?
1. What evidence do we have? (that’s today)
2. What are some of the potential and realized
consequences of a changing climate? (that’s
tomorrow)
3. What are the challenges to addressing climate
change? (why is it so hard?)
4. What are some of the ways we can combat
climate change (i.e. halt it and/or reverse it)
5. What have we already done? Did it work?

7.  http://www.smithsonianmag.com/videos/clim
 http://www.youtube.com/watch?v=M2Jxs7l

8. Studying volcanoes helps us
understand climate change
 June 1991: Mount Pinatubo
(Philippines) exploded
 Airborne pollutants, deaths,
and damage
 Affected climate temperature -
cooled the air for 15 mo.
 Like a test for scientists
 Climate predictions based on
the forecasts of James Hansen
of NASA and many others-
were the models
accurate?
 YES

14. Big Idea #1
 The overwhelming
scientific consensus
is that the earth’s
atmosphere is warming
rapidly, mostly because
of human activities, and
that this will lead to
significant climate
change during this
century.

15. Temperature and
Climate Change are
not new
 Volcanic emissions
 Solar storms
 Continental drift
 Meteors
 Glacial (ice ages) and
interglacial periods
 It’s been pretty stable for
the last 10,000 years

16. How do we know what the
climate was like in the past?
1. Air bubbles in ice cores
2. Radioisotopes in rocks
and fossils
3. Plankton in ocean
sediments
4. Tree rings
5. Pollen in lake bottoms
http://scied.ucar.edu/ice-cores-studying-p

17. Ice ages (glacials)
 Geologic records and
atmospheric measurements
show:
 Over the last 900,000 years
there has been a steady cycle of
glaciations (ice ages) that last
about 90,000 years and
interglacials that last about
10,000 years
• We’re overdue for an ice age ;)

18. Our atmospheric history

19. The greenhouse effect
 Good! :)
 Warms the earth by trapping some
of the heat radiating off the surface
of the earth
 The work of certain gasses in the
atmosphere
 CO2, CH4, H20, N2O

20. Climate Change and Human
Activities
 Humans have added more
greenhouse gases to the
atm. by
 Burning fossil fuels <--
most
 Farming/Ag (clearing
forests/grasslands, cows CH4)
 Use of inorganic fertilizers (rice
mostly, adds N2O)
 Burning forests
 Greenhouse gas levels are
the highest since 160,000

21. It IS getting warmer
 Is it because of human
activities?
 Evidence says yes
 Intergovernmental Panel
on Climate Change (IPCC)
 Formed in 1988 to evaluate
climate
 Use several levels of
certainty
• Virtually certain (more than 99%
probability)
• Very likely (90-99% probability)
• Likely (66-90% probability)

22. Who is the IPCC?
 More than 2,500 climate
experts from more than 130
countries
 Collect data from more than
29,000 experiments and
trials
 Found that it is virtually certain that
the troposphere is getting warmer due
to human activities
 In 2007 shared the Nobel Peace Prize
with Al Gore for alerting the world to
the dangers of global warming

23. CO2
Methane
(CH4)
Temp
Sea
level
What
pattern
do you
notice
among
the 4?

24. Quick Think
 How would you explain to someone how
we know what the climate was like
100,000 years ago?

25. So what is
the
evidence?
 8 key
findings:
1. The 20th
century
was the
hottest
century of
the past
1000
years

26. 2. Averaged over all land and ocean
surfaces, temperatures
warmed roughly 0.85ºC from 1880
to 2012, most of that since 1980

27. 3. The 10 hottest years since 1861
have been after 1990

28. 4. Over the past 50 years, Arctic4. Over the past 50 years, Arctic
temps have risen almost 2x as fasttemps have risen almost 2x as fast
as those in the rest of the worldas those in the rest of the world

29. 5. Glaciers and floating sea ice in
some parts of the world are melting
and shrinking at increasing rates
Melting of Alaska’s Muir Glacier
between 1948 and 2004 and 2004

30. 6. Warmer temps in Alaska and6. Warmer temps in Alaska and
Russia are melting the permafrost,Russia are melting the permafrost,
releasing more greenhouse gasesreleasing more greenhouse gases
into the atmosphereinto the atmosphere

31. 7.the world’s average sea level rose
by 10-20 cm (4-8 inches)

32. 8. Atmospheric CO2 levels have
steadily increased with
temperature