Transcript Student Climate Change Research, 2008

Student Climate Change Research:
Challenges and Opportunities
David R. Brooks, PhD
President, Institute for Earth Science Research
and Education
[email protected]
www.pages.drexel.edu/~brooksdr
Thailand workshops,
January, 2009
Introduction
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Climate change is one of the most important science
and public policy challenges for the 21st century.
Today's students will, as adults, inhabit a world that
may be much different from the present world.
Can students and teachers promote understanding of
climate change science?
Can students and teachers contribute to climate
science?
What is Climate?
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Climate is not the same as weather, which includes
short-term fluctuations due to seasons and movements
of air masses, for example.
Climate can refer just to regions or the entire planet.
● average meteorological conditions in a
particular place (30-year averages)
● global conditions (over 1000s of years and
longer)
“Climate is what you expect. Weather is what you get.”
(science fiction author Robert Heinlein)
What is “Global Climate Change”?
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“Global climate change” means that average conditions
on Earth are changing. In general, these changes have
been associated with global warming.
Regional climate changes are already known to be
occurring (e.g., melting of the Arctic ice cap and the
retreat of glaciers). These changes are occurring
rapidly by historical standards and, in some cases,
more rapidly than scientists predicted.
Most Earth scientists agree that although future ice
ages eventually will occur, currently the entire planet is
getting warmer more quickly than in the past, and this
will cause dramatic global disruptions unless it can be
controlled.
Over the last decade or so, some evidence suggests
that global warming has temporarily paused.
Thailand's Climate
(Describing a regional climate):
Thailand has a tropical climate with high
temperatures and high relative humidity. It is dominated by
the monsoon cycle. April and May are the hottest months.
June brings the start of the monsoon season, a rainy period
that lasts through October. Temperatures are somewhat
cooler in November through February, with lower humidity
and northeast breezes. The north and northeast are
generally cooler than Bangkok between November and
February, and hotter in summer. Temperatures in Thailand
never fall below freezing (0°C).
Temperature and Precipitation
Trends in Thailand, 1951-2002
http://www.greenpeace.org/raw/
content/international/press/reports/
crisis-or-opportunity-climate.pdf
(from Thailand Meteorological Office)
Global Climate
Temperature
inferred from
O18/O16 ratios. CO2
measured in
trapped air bubbles.
CO2 and
temperature are
positively
correlated, but
which is the cause
and which is the
effect?
Most climate
scientists believe
that increasing
levels of CO2 are
now causing global
temperatures to
rise (the
greenhouse effect).
(Data from Russian Vostok Station ice cores, east Antarctica,
a joint Russian, U.S., and French project.)
Global Climate Since the
Last Ice Age
(Data from ice and sediment cores around the globe.)
Recent History
(Since start of Industrial Revolution.)
Possible Effects of Climate Change
in Southeast Asia
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Sea levels may rise. Bangkok and its surroundings
are within 1 m of present sea level. Valuable
coastal farmland will be lost. Disappearance of
beaches will hurt tourism.
There may be reduced rice production due to loss
of land, higher temperatures, and changing rainfall
patterns.
There will be consequences if farmers and
fishermen cannot adapt to changing conditions.
Spontaneous migration of large populations could
be financially disruptive and create more serious
social and environmental problems.
Higher temperatures demand more air conditioning,
which increases greenhouse gases and contributes
to the urban heat island effect.
What Can We Do About Climate
Change?
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Quantify indicators of climate change.
Attempt to understand what kinds of
human activities are contributing to
climate change.
Make responsible personal and community
choices about how we use energy.
Hold our governments responsible for
investing in and implementing policies that
protect the environment and move beyond
an economy based on fossil fuels.
The First Big Question:
Can students contribute to
climate change research?
My answer:
Yes, but it is not easy!
The Second Big Question:
Should students contribute to
climate change research?
My answer:
Yes, because hands-on research is an
essential part of the science process.
But, does research need to be an essential
part of the science education process?
Countries, schools, teachers, and students
must decide for themselves.
Studying Global Climate
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Satellite measurements play a major role in
understanding global climate (and weather).
However, ground-based measurements are still
very important for understanding how to
interpret space-based measurements.
Can students collect data locally that contribute
to understanding global climate?
How can teachers help their students relate their
local weather and climate to the global “big
picture”?
How Do We Do It?
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Understand the problems and ask the right
questions.
Form partnerships among scientists, teachers, and
students, and their institutions.
Make long-term institutional commitments that do
not depend just on individuals.
Make the equipment investments required to
produce high-quality data. (Sometimes these
investments can be small!)
Follow international standards for data collection.
Use automated data collection whenever
appropriate.
Make a commitment to long-term data quality.
Focus on local measurements that are related to
climate change.
What Can We Measure?
In this presentation, we will consider:
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The sun
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Earth’s atmosphere
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Earth’s surface
Bringing the Sun Down to Earth
Weather and climate are controlled by the sun’s interaction
with Earth’s surface and atmosphere. This is a basic topic
for Earth science education. There are many measurements
students can make to improve understanding of these
interactions.
Organizing Climate-Related Measurements
Relating the Local to the Global
Local Student Activity
Regional/Global Measurement
air temperature
climate warming or cooling
surface temperature
radiative balance
soil temperature
radiative balance, land use changes
surface reflectivity
albedo (reflectivity)
aerosols and water vapor
transport of pollutants, changing cloud
patterns, land use changes, biomass
burning
precipitation
regional climate changes
sky photography, solar aureole
changes in air quality
solar radiation (pyranometry)
changes in air quality, cloud patterns,
radiative balance, site analysis for solar
applications
Some Things Students and Teachers
Can Do
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Photographing the solar aureole and the
sky
Radiometry – recording total insolation
and UV irradiance
Sun photometry – recording changes in
aerosol optical depth and water vapor
Reflectivity – monitoring changes in
surface reflectance (albedo)
Air and soil temperatures – monitoring
long-term changes in soil temperature
(related to soil moisture)
The Sun
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Our sun is an “average” star.
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It generates a power E of about E=3.9×1026 W, radiated
uniformly in all directions.
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The intensity of radiation decreases as the inverse square
of the distance from the sun.
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The solar constant is defined as the average power per unit
area of solar radiation at Earth’s average distance from the
sun, R:
So = E/(4π R2) = 1370 W/m2
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The amount of energy Earth receives depends on the time
of year. It varies from
Smax = So/(1 - e)2 = So/(0.983)2 = 1417 W/m2 in January
Smin = So/(1 + e)2 = So/(1.017)2 = 1324 W/m2 in July
Observing The Sun
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Most measurements of the sun lie
beyond the capabilities and
resources of students.
However, a “solarscope” can be used
to observe sunspots and measure
the sun’s rotation.
Sunspots viewed through haze
from forest fires in southern
California, late 2003 (NASA)
The Atmosphere
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The atmosphere is a very
thin layer of gases (<100
km) that make the
difference between a
habitable planet and one
that would not support
advanced life as we
understand it.
The atmosphere and its
constituents reflect,
scatter, and absorb
sunlight.
Table 2.2. Composition of pure dry
air near Earth’s surface.
Gas
Percent by Cumulative
volume
percent
(dry air)
by volume
N2
78.08
78.08
O2
20.95
99.03
Ar
0.934
99.964
Other trace 0.036
gases
100.000
Trace Gases in the Atmosphere
Table 2.3. Trace gases in the atmosphere.
Component
Approximate percent by volume and parts
per million (ppm)
Water vapor (H2O)
0 – 4%
Carbon dioxide (CO2)
0.037% (370 ppm)
Methane (CH4)
0.00017% (1.7 ppm)
Nitrous oxide (N2O)
0.00003% (0.3 ppm)
Ozone (O3)
0.000004% (0.04 ppm)
Aerosols (liquid qne solid particles)
0.000001-0.000015% (0.01-0.15 ppm)
Chlorofluorocarbons (CFCs)
0.00000002% (0.0002 ppm)
The Greenhouse Effect
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Some scientists define a “habitable zone” around a star as the
range of distances over which water can exist naturally as a liquid.
Does Earth fall within this zone?
The Earth/atmosphere system must be in radiative balance:
incident energy = (πr2)So
absorbed energy = (πr2)So(1 – A)
emitted energy = (4πr2)σT4
Emitted energy must equal absorbed energy, on average:
(πr2)So(1 – A) = (4πr2)σT4
or
So(1 – A) = 4σT4
Solve for T, using A=0.3 (average global albedo):
T = [So(1 – A)/(4σ)](1/4) = [1370•(1 – 0.3)/(4•5.67×10-8)](1/4)
= 255 K = -18°C
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So, Earth lies outside the habitable zone!
The Greenhouse Effect
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How can Earth support advanced life if it
lies outside the habitable zone?
Earth’s actual average surface
temperature is about 16°C. This is made
possible by trace gases (“greenhouse
gases”), including water vapor, in the
atmosphere”
So(1 - A) = 4σT4(1 – x)
where x is a “greenhouse parameter.” For
Earth, a value of about 0.4 produces an
equilibrium temperature of about 16°C.
Observing The Atmosphere
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Some properties of the atmosphere can be
observed directly:
● clouds (type and coverage)
● visibility (haziness)
● solar aureole (with a camera only!)
Other properties can be measured
indirectly from Earth’s surface:
● aerosols
● water vapor
Sky Photography
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The “aureole” is the circular region of lightcolored sky around the sun. It is caused by
scattering from dust and other aerosols in the
atmosphere. A very clear sky produces a small
aureole, and a very “dirty” sky can produce a
very large aureole.
Digital photographs of the sun can be analyzed to
determine the size of the aureole, which can be
related to atmospheric conditions, including
aerosols.
Photos of the sky, pointing away from the sun,
can also be related to air pollution and aerosols.
Sky Looking North at Solar Noon
Twilight Glow from Polluted Sky
Photographing the Solar Aureole
Do NOT look through
an optical viewfinder!!
Direct sun photos may
damage a digital
camera.
Canon PowerShot
A530, F5.6 @ 1/1600 s.
Use the same F-stop
and shutter speed
for every photo.
ImageJ software, available as a free download
From http://rsb.info.nih.gov/ij/download.html
How Does Sky Photography
Become Climate Science?
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Always use the same camera – one with manual settings for
focus, exposure time, and f-stop.
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Use the same f-stop and exposure settings, and focus at
infinity. (Do not use “automatic” settings.)
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Use the highest resolution that your camera supports.
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Always photograph the same scene, and include a little land
or water below the horizon, to track seasonal changes on the
ground.
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Photograph the scene at the same time of day, for example,
sunset or solar noon.
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Do not apply digital enhancements or resize or compress the
image.
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Collect images regularly over long periods of time.
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Keep careful records about scenes, dates, times, and camera
settings, including your latitude, longitude, and elevation.
Earth’s Surface
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There are two basic areas of interest:
● weather
● climate
Weather is easy to measure, but climate is
not!
Weather measurements can be made over
short periods of time. Climate must be
measured over very long periods of time.
Climate measurements require a longterm institutional commitment.
Measurements at Earth’s Surface
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Basic meteorological measurements (air
temperature, wind, precipitation, relative
humidity)
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Solar radiation
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Soil/water temperature
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Surface temperature
and reflectivity
Measuring Air Temperature
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The international standard is a “Stevenson screen”
The GLOBE thermometer shelter is smaller. Are
temperatures different? I don’t know.
Stevenson screen
80 x 61 x 59 cm
GLOBE shelter
50 x 28 x 20 cm
Air and Soil Temperature in Pennsylvania
Does Anybody Need More
Temperature Measurements?
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Yes! There are hardly any long-term
simultaneous records of air temperature and soil
temperature.
These data are important for agriculture and pest
management.
Changes in soil temperature can be indicators of
climate change (for example, melting
permafrost).
The relationship between soil and air temperature
depends on soil moisture, another indicator of
climate change (in tropical climates?).
Measuring Insolation:
Student Pyranometer Data
Site Evaluation for
Solar Power
1-minute values of insolation…
integrated over 24 hours.
Cloud Climatologies in Texas
1-hr means and
standard deviations of
1-min samples
Broadband and Near-IR Reflectivity
UV Radiometry
Smoke in the atmosphere reduces
UV radiation reaching Earth’s surface.
This can disrupt ecosystems and may
be associated with bird flu.* UV-A
radiation can be monitored with a
relatively inexpensive (~$150) radiometer.
It uses a blue LED that responds to
radiation with a strong peak around
372 nm.
*
Mims, Forrest M. III.
Avian Influenza and UV-B Blocked by Biomass Smoke.
Environmental Health Perspectives, 113, 12, 806-807, December 2005.
Measuring Aerosols
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Sun photometers can be used to
monitor absorption and scattering of
sunlight by particles in the atmosphere
(aerosols), by measuring the “aerosol
optical thickness.”
The effects of aerosols are one of the
larger uncertainties in computer
models used to predict future climate.
The sun photometer shown here uses
LEDs to measure aerosol optical
thickness at green and red
wavelengths.
Hundreds of these instruments have
been used around the world, with
student data included in papers
published in peer-reviewed science
journals.
Aerosols in Rural Arkansas
Aerosols in Puerto Rico
Water Vapor in Puerto Rico
Conclusions
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I have briefly described some ways that scientists, teachers,
and students can work together to understand Earth’s climate.
Other scientists will have other ideas.
Students CAN make significant contributions to climate
science research, because predictions of future climate
depend on having many sources of reliable long-term data.
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The stable physical environment around schools provides
major advantages for this kind of research.
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Climate change research must be conducted over the long
term – years, rather than months.
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School-based student research must be chosen carefully and
conducted in collaboration with scientists.
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School administrators and the education establishment must
be willing and able to provide long-term institutional support,
including science support that goes beyond what is required
just to meet educational objectives.
Thank you for the opportunity to
discuss student/teacher roles in
understanding and measuring climate
change.
I hope there are many questions!