Basic Science of Climate Change. Presentation given for a group of Road Scholars at the Adobe Resort in Yachats, Oregon.

1. Weather & Climate Change
Andreas Schmittner
Road Scholar, Feb. 27, 2019

2. What Do You Think Is
The Difference Between
Weather and Climate?

3. https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?or1862
Weather

4. Weather & Climate

5. Climate

6. We’re still in a drought!
McKenzie Pass
https://wcc.sc.egov.usda.gov/nwcc/view?intervalType=View+Current+&report=WYGRAPH&timeseries=Daily&format=plot&interval=WATERYEAR&sitenum=619&wateryear=

7. http://library.open.oregonstate.edu/climatechange/
http://ipcc.ch/report/sr15/ https://science2017.globalchange.gov/

8. https://www.ncdc.noaa.gov/cag/global/time-series/globe/land_ocean/ytd/12/1880-2018
Anomalies with respect to 1910-2000 average

9. https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/
Anomalies with respect to 1955-2006

10. glaciers shrinking worldwide
Muir Glacier, SE Alaska
USGS & NPS photographs
1941
1950
2004
Melting of mountain glaciers
contributes about 1 mm/yr to sea
level rise

11. https://climate.nasa.gov/vital-signs/ice-sheets/
Sea Level Contribution
0.75 mm/yr
Sea Level Contribution
0.25 mm/yr
Greenland
Antarctica

12. http://www.columbia.edu/~mhs119/SeaLevel/
Glaciers = 1 mm/yr
Ice Sheets = 1 mm/yr
Ocean Thermal Expansion = 1 mm/yr
(~8 in)

13. https://www.esrl.noaa.gov/gmd/ccgg/trends/full.html

14. CO¿flux(GtC/yr)
Global Carbon Project
Data: CDIAC/NOAA−ESRL/GCP
Atmosphere
Land sink
Ocean sink
Land−use change
Fossil fuels
and industry
1900 1920 1940 1960 1980 2000 16
−10
−5
0
5
10
Total estimated sources do
not match total estimated
sinks. This imbalance reflects
the gap in our understanding.
http://www.globalcarbonproject.org/carbonbudget/
Cumulative emissions
(area under grey curve)
= 500 Gt = 0.5 Tt

15. =3.7xGtC
1 gallon gas = 5 pounds of carbon
1 t = 2200 pounds = 440 gallon gas
Each American emits 4.5 tC/year

16. Expected Impacts from
Continued Carbon Emissions
• More warming
• More melting of snow and ice
• More sea level rise
• More shifts in vegetation and ecosystems

17. Tundra
Taiga
a.k.a. Boreal Forest
Boreal forest will replace tundra.
What other animals live in the tundra?

18. Other Concerns
•Irreversibility
•Extreme Events (Droughts, Floods, Hurricanes)
•Positive Feedbacks
•Permafrost Melting
•Tipping points
•Ice Sheet Collapse
•Ocean Circulation Slowdown/Collapse
•Ocean Acidification

19. Unequal Distribution of Climate Change

20. km
accumulation
meltingHE
ice flow
equilibrium line
** *
*
distance km
H
H = average ice sheet height
distance km
km
HE
** *
*
• Equilibrium line rises.
• More surface are is below equilibrium
line in melt zone.
• Increased melting.
H
* *
*
HE
* * *
*
H
• Ice sheet shrinks and elevation drops.
• Because at lower elevation
temperatures are higher, even more
melting occurs.

21. Melting
Ice Sheet Elevation-Mass Balance Feedback
Lower Surface
Elevation
Warmer
Temperatures
+
positive
feedback
• Positive feedback leads to a threshold for the
equilibrium line.
• If higher than average ice sheet height, the ice sheet
will disappear.
• It will only grow back if equilibrium line is decreased
below zero (ground), that is below its current
elevation. Irreversibility.
• Greenland is close to threshold.Vulnerable to
warming. 1.5°C global mean warming will lead to its
irreversible demise (Robinson et al., 2012, Nat. Clim.
Change DOI: 10.1038/NCLIMATE1449).
• East Antarctic ice sheet is not close to the
threshold. May even grow due to increased snowfall
in warmer climate.
threshold

22. Greenland Ice Sheet = 7 m sea level rise
West Antarctic Ice Sheet = 5 m sea level rise
4xCO2
Complete melting will take many centuries or even thousands of years.

23. West Antarctic Ice Sheet
Vulnerable to sea level rise because much of its
grounding line is below sea level.
Sea level rise could make parts of it float.Warming
ocean melts ice shelves from below. Removing ice
shelves can speed up the ice sheet flow. Its
disintegration would lead to 6 m of sea level rise.
Huybrechts 2009 Nature

24. Antarctic Ice Sheet Projections
DeConto and Pollard (2016) Nature

25. Long-Term
Changes
Clark et al. (2016)
Nature Clim. Change

26. Clark et al. (2016) Nature Clim. Change
Long-Term
Changes

27. Clark et al., 2018, Nature Climate Change, https://doi.org/10.1038/s41558-018-0226-6
Sea Level Rise

28. Bakker et al. (2016) Geophysical Research Letters, doi: 10.1002/2016GL070457
Ocean Circulation
Atlantic Meridional Overturning Circulation (AMOC)

29. Permafrost
Koven et al., 2015, Phil. Trans. R. Soc. A 373, http://dx.doi.org/10.1098/rsta.2014.0423
Additional carbon (and
methane) input to atmosphere
but no runaway feedback.
10% Effect
+10-20 GtC
+30-100 GtC

30. Extreme Events
• Heat waves will become more common
• Cold spells will become less common
• Number of tropical cyclones (Hurricanes) will not increase
but we’ll get more strong ones (Cat 4 & 5 will increase)
• More droughts, more flooding due to intensification of
water cycle
• More wildfires

31. 31

32. Calcifying Organisms
32
Ca2+
+ CO3
2− ⎯ →⎯← ⎯⎯ CaCO3
Coccolithophores
Pteropods (Sea Butterfly)
Foraminifera
Coral
Calcite
Aragonite

34. What can we do?

35. IPCC SR15 Fig. SPM3a

36. Climate Change
•Its real
•Its us
•Its serious

37. We can do something
about it!

38. Thank You!