Transcript CO 2 Concentration (ppmv)

Global Climate Change
Chapter 13-3
The
Greenhouse Effect
Some solar radiation
is reflected by the
Earth and the
atmosphere
Solar
radiation
passes
through
the clear
atmosphere
Some of the infrared radiation
passes through the atmosphere,
and some is absorbed and
re-emitted in all
directions by
greenhouse gas
molecules. The
effect of this
is to warm
the Earth’s
surface and
the lower
atmosphere.
Infrared radiation is emitted
from the Earth’s Surface
Most radiation is absorbed by the
Earth’s surface and warms it
We know about the effects of
Greenhouse Gases (GHG)
1.Carbon dioxide*
2.Methane* - CH4
3.Nitrous oxide* - N2O
4.CFCs – chlorofluorocarbons**
5.Water vapor
*These are increasing due to human activities, primarily
burning of fossil fuels
** Being phased out, but persist in the atmosphere for
decades
Primary Pollutants
CO
SO2
CO2
NO
NO2
Most hydrocarbons
Most suspended
particles
Secondary Pollutants
SO3
HNO3
H2O2
H2SO4
O3
PANs
Most NO3– and SO42 – salts
Sources
Natural
Mobile
Stationary
Examples of Greenhouse Gases
Affected by Human Activities
• The main thing that contributes to greenhouse gas
emissions is the burning of fossil fuels since the Industrial
Revolution
• How does the pre-industrial level of CO2 compare to 1999?
CO2
Pre-industrial concentration
Concentration in 1999
100 year Global Warming Potential
Atmospheric lifetime (years)
288 ppmv
366 ppmv
1
50-200a
CH4
N2O
848 ppbv
1800 ppbv
21
12b
285 ppbv
312 ppbv
310
120
CO2 Concentrations Over the
Past 1000 Years
CO2 Concentration (ppmv)
CO2 Concentration (ppmv)
380
360
340
320
380
360
340
320
300
280
1850
1900
1950
2000
300
280
260
800
1000
1200
1400
Year
Source: Based on IPCC (1994)
1600
1800
2000
Data on ice core samples taken in Antarctica give us a
picture of climate that goes back thousands of years
Map of the continent of Antarctica
Atmospheric gases and particles are trapped in the ice and can
be analyzed to determine the composition of the atmosphere at
different points in time. The deeper the core, the longer ago the
ice was laid down. This one-meter long section of ice core from
the West Antarctic Ice Sheet project shows a dark ash layer.
(Photo credit: Heidi Roop)
Atmospheric carbon dioxide does vary over time
What relationship do you see between temperature
and CO2 levels? Does one go up first?
What makes the temps go up in the first place?
Milankovitch cycles – periodic changes in earth’s orbit begin the
warming periods (end of ice ages)
With warmer temps, more CO2 goes into the atmosphere from
the oceans, which raises temps even more
This is called a positive feedback system
Look at this graph again.
What is the highest level of CO2 in ppm over the last 400,000
years (except for the present)?
Current levels of atmospheric CO2 : higher
than they have been in recorded history
http://co2now.org/
This data is
from Feb.
2012
Latest data from Feb. 2013
Atmospheric carbon dioxide levels 1960-2000
This graph is called the Keeling Curve – famous graph you should know!
This is data collected at a station in the Pacific from 1960-2000
Keeling was one of the first scientists to document the consistent rise in CO2
levels
Notice the yearly cycle going up and down – can you explain this?
But overall, the trend is clearly upward
Time-lapse history of human global CO2 emissions
http://www.youtube.com/watch?v=kqV-kx2ClXU&feature=related
So if CO2 levels are correlated with temperature, then we
expect global temps to rise since the levels of CO2 have
risen. And that is what we see…..
Global Warming Data from NOAA
•
This graph shows annual mean global
temperature anomalies over the period
1880-2001.
The zero line represents the long term
mean temperature from 1880-2001, and
the red and blue bars are showing annual
departures from that mean.
As is evident in the graph, 2001 was
second only to 1998 in terms of global
temperature, and the trend has been
toward increasing temperatures at least
since the beginning of the 20th century.
Land temperatures have greater
anomalies than the ocean, which is to be
expected since land heats up and cools
down faster than water.
Graphic showing global temperatures
warming since 1880
http://www.nasa.gov/topics/earth/features/2011-temps.html
2010 According to NOAA scientists, 2010 tied with 2005 as the
warmest year of the global surface temperature record,
beginning in 1880. This was the 34th consecutive year with
global temperatures above the 20th century average.
2011 NASA reports 2011 was the ninth warmest year on record
What about 2012? See next slide.
10 warmest years on record
(°C anomaly from 1901–2000 mean)
Global[63]
Year
Land[64]
Ocean[65]
2010
0.6590
1.0748
0.5027
2005
0.6523
1.0505
0.5007
1998
0.6325
0.9351
0.5160
2003
0.6219
0.8859
0.5207
2002
0.6130
0.9351
0.4902
2006
0.5978
0.9091
0.4792
2009
0.5957
0.8621
0.4953
2007
0.5914
1.0886
0.3900
2004
0.5779
0.8132
0.4885
2012
0.5728
0.8968
0.4509
2012 is in the top 10 warmest years, too.
What evidence do we have that human activities
are the cause of global warming?
Radioisotopes of carbon in the atmosphere have
revealed that more and more of the carbon is
the type found in fossil fuels, and a lower
percent is the type of carbon that has normally
occurred in the atmosphere.
IPCC –
• Intergovernmental Panel on Climate Change
• Established to be an objective source of information on climate
change for policy makers worldwide
• made conclusions and reports based on many scientific studies
• 2001 IPCC released third report – “states baldly that global
warming, unprecedented since the end of the last ice age, is ‘very
likely’”; debate among scientists is effectively ended
• 2007 IPCC concluded with statistical certainty (90%) that human
activity is contributing to global warming
See their report:
http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf
Nobel Peace Prize
Nobel Peace Prize was awarded in 2007 to Al
Gore, former Vice President of U.S., and the
IPCC for work on the issue of climate change
What does global warming have to do with
world peace?
Scientific consensus
There is scientific consensus that global climate change in
happening and that human activity is the cause. There is
not really any more debate in the scientific community.
There are still a few people who are considered climate
skeptics, but not very many. Some of these “contrarians”
are the same people who were skeptical of and argued
against the dangers of tobacco, the threat to the ozone
layer, and the cause of acid rain – all of which have been
scientifically proven to be true.
See the book Merchants of Doubt and the website Union
of Concerned Scientists for more information.
Consequences of global warming
1. Rising sea levels – due to
(1) melting of glaciers and
polar ice (documented
already)
(2) thermal expansion of
ocean at warmer temps
How will this affect polar
regions? Islands? Coastal
cities?
Documented sea level rise from 1880-2000
Effects of a 1m rise in sea level
Areas in red will be flooded if sea levels rise 1m
2. Dwindling Arctic and Antarctic sea ice
Another example of positive
feedback – as the ice melts, there is
less white and more dark surface to
absorb radiation from the sun. This
is called decreased albedo, or
reflectivity. Temperatures go up even
more.
What does this tell you?
Since 1995 Reports
of Antarctic ice
shelves breaking
up (predictions
coming to reality)
Consequences of global warming
3. Melting permafrost
Permafrost is a carbon sink and when it melts, releases more
carbon into the atmosphere, making global warming even worse
– another example of positive feedback
Studies have already documented that this is occurring.
4. Human health problems
• More problems with mosquitoes, diseases they
transmit
• Ground-level ozone increases, leading to breathing
problems
HEALTH EFFECTS OF CLIMATE CHANGE
Urban Heat Island Effect
CLIMATE
CHANGE
Air Pollution
Vector-borne Diseases
Temperature Rise 1
(Sea level Rise 2)
Water-borne Diseases
Hydrologic Extremes
1
2
2°C by yr. 2100
49 cm “ “
IPCC estimates
Source: Jonathan Patz, 1998
Heat Stress
Cardiorespiratory failure
Respiratory diseases, e.g.,
COPD & Asthma
Malaria
Dengue
Encephalitis
Hantavirus
Rift Valley Fever
Cholera
Cyclospora
Cryptosporidiosis
Campylobacter
Leptospirosis
Water resources & food
supply
Malnutrition
Diarrhea
Toxic Red Tides
Environmental Refugees
Forced Migration
Overcrowding
Infectious diseases
Human Conflicts
Consequences of global warming
5. Changes in weather patterns, such as more
severe storms, changes in precipitation
The frequency of downpours and heat waves,
as well as the power of hurricanes, has
increased so dramatically that "100-year
storms" are striking some areas once every 15
years
Hurricanes increase in strength over
warm water, could become more intense
with global warming
Consequences of global warming
6. Agriculture
Decrease in crop yield due to drought, floods
Some areas will have higher yields due to longer
growing season
Increased need for irrigation
Consequences of global warming
7. Effects on plants and animals
Organisms in ecosystems are adapted for certain climate and if that changes,
plants and animals there may not survive (adaptation in plants and
animals takes time and global warming is changing things quickly),
Ex: polar bear – threatened by loss of sea ice that is necessary for successful
hunting,
Ex: golden toad of Costa Rica’s cloud forest – now extinct due to climate
change there
Coral bleaching occurs at warming temps – only
takes a sustained increase of about 1°C for
corals to bleach
Healthy coral reef with high
biodiversity
Bleached coral reef with low biodiversity
Current and Projected Ranges of Sugar Maple
Prediction based on increased
temperature
Present Range
Source: Redrawn from Davis and Zabinski, 1992
Prediction based on increased
temperature and moisture reduction
Overlap
Predicted Range
Consequences of global warming
Consequences of global warming
UAB researchers have documented that king crabs,
once absent from the Antarctic, are invading because
the ocean temperatures are warmer. This is bad news
for the species that live there which are not adapted
to survive predation by shell-crushing crabs.
Consequences of global warming
8. Ocean acidification –
• normal ocean pH is close to 8 but it is dropping due to addition of CO2 which
forms an acid in the water
• Shelled organisms can’t handle the lower pH and are being affected
• Sea urchin larvae don’t develop normally – UAB research
Kyoto Protocol, 1997
International agreement to reduce
greenhouse gas emissions
About 120 countries agreed, U.S.
has not
U.S. objections: negative
economic impacts, developing
countries not held to same
protocol as developed countries
(not seen as fair)
Expires in 2012
Copenhagen Accord, 2009
U.N. sponsors a yearly meeting of many of the world’s countries
to discuss global climate change
Recent outcome: Copenhagen Accord – non-binding agreement
to combat climate change
Some of the main points:
• Recognizes the scientific view that an increase of 2°C should be the limit in
order to combat climate change
• Countries set goals to reduce in GHG emissions
• Reduction in deforestation is critical
• Endorsed continuation of Kyoto Protocol
• Funding/incentives should be provided to
developing countries
Copenhagen Accord, 2009
Criticism
• Not a legal agreement
• Was drafted by only 5 countries
• Does not say where funding will come from
• Sets no real targets for emissions reductions
• Countries only “took note” of the accord, did not adopt it
Summary of global warming/cooling
components:
What can we do to reduce CO2 emissions?
Increase energy efficiency – use less fossil fuels
Use cleaner fossil fuels, i.e., natural gas
Government intervention – i.e., laws, tax incentives,
international agreements
Carbon sequestration
Also called Carbon Capture and Storage (CCS)
Cap and trade, or carbon credits
Develop and use alternative fuels that produce
little or no CO2
More on this in the unit on energy
Summary video to end with….
http://www.youtube.com/watch?v=KYLGBIiq6Wg