Transcript AOSS_NRE_480_L11_Abrupt_20140220

Climate Change: The Move to Action
(AOSS 480 // NRE 480)
Richard B. Rood
Cell: 301-526-8572
2525 Space Research Building (North Campus)
[email protected]
http://aoss.engin.umich.edu/people/rbrood
Winter 2014
February 20, 2014
Class News
• Ctools site: AOSS_SNRE_480_001_W14
• Something I am playing with
– http://openclimate.tumblr.com/
• Assignment
– Emailed
– Posted
Politics of
Dismissal Entry
Model
Uncertainty
Description
Projects
• Fracking (Omar, Jeffrey, Austin, Megan, Ranya)
– With the recent technological advances in hydraulic fracturing,
the U.S. has become the world’s largest producer of oil and is
projected to become an exporter of natural gas. Natural gas has
been posed as a “bridge fuel” to displace coal in the production
of electricity, and to reduce the emissions of carbon dioxide. As
a policy advisor on climate change, I need to know whether or
not a transition to natural gas serves to reduce the emissions of
greenhouse gases and the impact on water resources. I am
especially concerned about the leakage of methane and huge
amount of water that is required. I have another team working
on public health effects air quality and water quality are out of
your domain.
Projects
• Agricultural (Edwin, Rachel, Kathleen, Chris)
– The accounting of greenhouse gas emissions from agriculture is
difficult. I have read that something like 30% of the total
emissions are agriculturally related. This requires that those
emissions used in, say, fertilizer manufacturing are accounted in
agriculture rather than industry. Recently, I read a blog
http://www.wunderground.com/blog/RickyRood/greenhouseemissions-of-agriculture that said there was one group who
claimed all by itself, livestock was responsible for more than 52%
of the emissions. This seems enormous and challenges many
conventional strategies for greenhouse gas management. The
CEO of my company has announced a sustainability effort, and I
want to know what decisions my food manager can make the
matter to climate change, including water resources. Should I
emphasize vegetarian meals, or is it better to buy local,
“sustainable,” or organic?
Projects
• Air Travel (Meng, Arnav, Mason, John, Justin)
– There is no doubt that airplanes emit carbon dioxide and other
greenhouse gases. Air travel is an important part of the
economy. When I read about air travel and climate impacts, the
information is complicated. Often the discussion ends with the
admission that there are not obvious options to make air travel
and transport “sustainable” in the sense of climate change. The
European Union has been considering a way to reduce
emissions from air travel. Their efforts have only revealed even
more complexity in reducing the environmental impact of aircraft.
In order to know how much priority to give to sustainable air
travel in my research and development portfolio, I need a
knowledge-based assessment of the impact of air travel on
climate, risks associated with “doing nothing” and the viable
strategies for making air travel “sustainable.”
Today
• Scientific investigation of the Earth’s
climate: Foundational information
– “Internal Variability”
– Abrupt climate change
In Class Exercise (from last time)
• Economist:
– Temperature not going up, but carbon dioxide is.
Look! Warming has stopped.
Analysis of Problem
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Length of “trend”
Buffering by ocean
Internal variability
“presentation”
Sampling
Changes in forcing
– Aerosols
• Solar Variability
England et al. 2014
Pacific Decadal Oscillation
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Does the Pacific Decadal Oscillation operate
regularly lasting 20-30 years, and does
southern California experience droughts during
that period?
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The Pacific Decadal Oscillation is one of several
“oscillations” that are important to weather and climate.
Some attributes of the Pacific Decadal Oscillation
Pacific Decadal Oscillation: Basics
Colors: Sea Surface Temperature difference from long term average.
Arrows: Stress on the ocean surface caused by winds
Warm here
Better version of figure from JISAO
Cool here
Some information on Pacific Decadal Oscillation
• Joint Institute for Study of Atmosphere and
Ocean (JISAO):
– Pacific Decadal Oscillation
• Climate Prediction Center (CPC):
– 90 Day Outlook Summary
– Weather and Climate Linkage
• National Climatic Data Center (NCDC):
– Decadal Oscillations
• Review Paper from Rood Class References
– Mantua and Hare (2002) J of Oceanography
Bumps and Wiggles
• Rood’s Series on Bumps and Wiggles
Today
• Scientific investigation of the Earth’s
climate: Foundational information
– “Internal Variability”
– Abrupt climate change
Abrupt climate change
• The predictions and observations so far
are either in the sense of:
– Relatively small changes in the dynamic
balance of the climate system
– Incremental changes to the stable climate.
• What about “abrupt” climate change?
Abrupt Climate Change (NRC)
• Abrupt Climate Change (2013), National
Research Council
• Abrupt Climate Change (2002), National
Research Council
• Rood Summary Blog
• Wunderground: Abrupt Climate Change
What is a stable climate?
LIQUID - ICE
NOAA Paleoclimate
Younger Dryas
POSSIBLE EVIDENCE
OF CHANGE IN OCEAN
CIRCULATION
WHAT DOES THIS
MEAN?
Abrupt Climate Change
• Most scenarios of abrupt climate change are
related to a phase change in some way or
another. Does the albedo change quickly? Is
there a change in the fresh water in the ocean?
Is there a release of gas stored in something
that is frozen?
• It is also possible to define rapid changes in
ocean (land?) ecosystems, that leads to
composition changes in the atmosphere.
Biology – sensitive to temperature, water,
salinity, ph, etc.
Lamont-Doherty: Abrupt Climate Change
The Earth System: ICE
(Think a little more about ice)
non-polar
polar
glaciers
glaciers
and
(Greenland)
snow
(Antarctica)
sea-ice
Impacts regional
water supply,
agriculture, etc.
Solar reflection,
Ocean-atmosphere
heat exchange
Solar reflection,
Ocean density,
Sea-level rise
(Tour of the cryosphere, Goddard Scientific Visualization Studio)
The Cryosphere
• TOUR OF CRYOSPHERE: MAIN NASA
SITE
There could be changes in the way the atmosphere and
ocean transport heat
(An excursion to the North Atlantic)
• Remember that the atmospheres and ocean carry heat
from the equator to the pole.
– This is done at preferential locations.
– One especially important mechanism of heat transport is the Gulf
Stream, along the eastern coast of the U.S, which transports
heat to the North Atlantic. This keeps much of Europe much
warmer than it would be based on the position of the sun.
– The Gulf Stream is part of a large organized circulation in the
oceans.
• Connects north and south
• Connects top and bottom of ocean (which is not very common)
– This organized circulation is sometimes called the ocean
“conveyor” belt. It is named the thermohaline circulation
because it depends on both the thermal structure and the
saltiness (“haline”) of the water.
The Thermohaline Circulation (THC)
(Global, organized circulation in the ocean)
(The “conveyer belt”, “rivers” within the ocean)
Blue shading, low salt
Where there is localized
exchange of water between
the surface and the deep
ocean (convection)
Green shading, high salt
Warm, surface currents.
Cold, bottom currents.
From Jianjun Yin, GFDL, see J. Geophysical Research, 2006
Importance of the Thermohaline Circulation
in the Present Climate
If the
thermohaline
circulation
shut down,
then the
climate, the
mean surface
temperature,
would be
abruptly and
significantly
changed.
• The deviation of the surface air temperature from the zonal average
(NCAR/NCEP reanalyses);
• The THC is responsible for most northward heat transport in the Atlantic
(> 1 PetaWatts = 1015 Watts);
• High surface air temperature over the North Atlantic and Europe
From Jianjun Yin, GFDL, see J. Geophysical Research, 2006
Some aspects of the thermohaline circulation
• Salt is important to the density of sea water.
• Warm, salty water on the surface moves to high northern and
southern latitudes, where it sinks.
• The area where there is strong, localized exchange, bottom water
currents develop which return cold water towards the equator (heat
exchange).
• The area where there is strong localized exchange is significantly
warmer than it would be in the absence of the ocean currents. (see
next figure)
• Saltiness is very important. If the North Atlantic were flooded with
fresh water from Greenland ice melting or much more precipitation,
then the thermohaline circulation might shut down.
– There is evidence that this has happened before (look up the Younger
Dryas)
– Hence melting of Greenland impacts both sea-level rise and the
thermohaline circulation
Some model predictions of what would happen if
the thermohaline circulation shutdown
• From From Jianjun Yin, GFDL, see J.
Geophysical Research, 2006
• Fresh water is added in the model
simulation to the North Atlantic, in the
vicinity of Greenland and Iceland.
• With the addition of fresh water the
thermohaline circulation shuts down
• There are global consequences
– See plots below.
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Predicted Sea Surface Temperature
Bipolar Seesaw 3oC decrease NA
Extension of icy seawater and sea ice
coverage in North Atlantic
Spread of warmer seawater via ACC
Feedback on the THC intensity
(This dipole has the characteristic of a
dynamical response)
Predicted Sea Surface Salt (SSS)
1.2 psu decrease in 50~70oN belt
SA and Gulf of Mexico become more
saline
Sharp SSS gradient at 40oN
Labrador Sea: the most susceptible
region to freshwater perturbation
Predicted Sea Ice
Thickness increases and coverage
extends in the Labrador Sea
Thickness decreases in the Nordic
Seas the Barents Sea and the Weddell
Sea due to enhancement of deep
convection (part of a dynamical
response?)
From Jianjun Yin, GFDL, see J.
Geophysical Research, 2006
Abrupt climate change
• Changes in the ocean circulation.
– Remember Younger Dryas
• Remember the ice-age turn around:
– Need some sort of positive feedback to amplify the solar forcing
• Ice-albedo feedback //
– Sea ice collapse in Arctic?
– Land ice sheet collapse  sea level rise
• Sudden release or absorption of greenhouse gas from ocean
– Schmittner: Oceans & Greenhouse
• Sudden release or absorption of greenhouse gas from land
– Permafrost
• Sudden change in the biological balance of plants and animals
– Ocean temperature and acidification
Abrupt Climate Change:
Definition from NRC (2013)
• … changes “come faster than expected,
planned, or budgeted for, forcing more
reactive, rather than proactive, modes of
behavior”
Summary from NRC (2013)
• The near-term outlook: abrupt change in current trends incorporated
into planning and management during the next century.
– Likelihood is listed as low, moderate and high.
• Moderate:
– decrease in ocean oxygen
– increase in intensity, frequency and duration of heat waves
– increase in frequency and intensity of extreme precipitation events (droughts /
floods / hurricanes / major storms)
– rapid state changes in ecosystems, species range shifts and species boundary
changes
• High:
– late-summer Arctic sea ice disappearance and
– increases in extinctions of marine and terrestrial ecosystems
• Low:
– rapid destabilization of ice sheets leading to greatly accelerating sea level
The Arctic
Projected Global Temperature Trends: 2100
2071-2100 temperatures relative to 1961-1990.
Special Report on Emissions Scenarios Storyline B2 (middle of the road warming).
IPCC 2001
Let’s think about the Arctic for a while
• WWF: Arctic Feedbacks Assessment
• This assessment of the most recent science shows that numerous
arctic climate feedbacks will make climate change more severe than
indicated by other recent projections, including those of the
Intergovernmental Panel on Climate Change Fourth Assessment
report (IPCC 2007). Some of these feedbacks may even interact
with each other.
Arctic Feedback
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Atmospheric Circulation Feedbacks
Ocean Circulation
Ice Sheets and Sea-level Rise Feedbacks
Marine Carbon Cycle Feedbacks
Land Carbon Cycle Feedbacks
Methane Hydrate Feedbacks
What about the Antarctic
• Pine Island Glacier: Wikipedia
• Pine Island Glacier: Irreversible
Summary Points: Science
Correlated Observations
CO2 and Temperature Observed to be
strongly related on long time scales (>
100 years)
CO2 and Temperature not Observed to be
strongly related on short time scales (<
10 years)
Land Use / Land Change
Other Greenhouse Gases
Aerosols
Internal Variability
Theory / Empirical Evidence
CO2 and Water Vapor Hold Heat Near
Surface
Theory / Conservation Principle
Mass and Energy Budgets
 Concept of “Forcing”
Prediction
Earth Will
Warm
Validation
Evaluation
Consequences
Observations
CO2 is Increasing due to Burning Fossil
Fuels
Feedbacks
Air Quality
“Abrupt” Climate Change
Iconic and Fundamental Figures
Scientific investigation of Earth’s climate
SUN: ENERGY, HEAT
EARTH: ABSORBS ENERGY
EARTH: EMITS ENERGY TO SPACE  BALANCE
Sun-Earth System in Balance
SUN
EARTH
PLACE AN
INSULATING
BLANKET
AROUND
EARTH
The addition to the
blanket is CO2
FOCUS ON
WHAT IS
HAPPENING
AT THE
SURFACE
EARTH: EMITS ENERGY TO SPACE  BALANCE
Increase of Atmospheric Carbon Dioxide (CO2)
Primary
increase comes
from burning
fossil fuels –
coal, oil,
natural gas
Data and more information
Temperature and CO2: The last 1000 years
Surface temperature and CO2 data from the
past 1000 years. Temperature is a northern
hemisphere average. Temperature from
several types of measurements are consistent
in temporal behavior.
 Medieval warm period
 “Little ice age”
 Temperature starts to follow CO2 as CO2
increases beyond approximately 300 ppm,
the value seen in the previous graph as the
upper range of variability in the past
350,000 years.
The Earth System
SUN
CLOUD-WORLD
ATMOSPHERE
ICE
(cryosphere)
OCEAN
LAND
Radiation Balance Figure
Radiative Balance (Trenberth et al. 2009)
1998
Climate Forcing
(-2.7, -0.6)
2001
Hansen et al: (1998) & (2001)
(-3.7, 0.0)