Transcript bioch5 - Otterville R

Biodiversity:
Who cares?
Which do you like better?
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Which do you like better?
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Which do you like better?
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Which do you like better?
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Which do you like better?
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Which do you like better?
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Which do you like better?
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What do you think biodiversity
means?
Biodiversity
What does “Bio” mean?
Bio =
Biodiversity
What does “Diversity” mean?
Diversity = Variety
Biodiversity is the variety of life on
Earth and the essential
interdependence of all living things
• Scientists have identified more than 2 million species. Tens
of millions -- remain unknown
•The tremendous variety of life on Earth is made possible by
complex interactions among all living things including
microscopic species like algae and mites.
There are 3 components of
biodiversity
1.
Diversity of genes
Chihuahuas, beagles, and rottweilers are all dogs—but
they're not the same because their genes are different.
Chihuahua
Beagle
Rottweilers
There are 3 components of
biodiversity
Diversity of species
For example, monkeys, dragonflies, and
meadow beauties are all different species.
Saki Monkey
Golden Skimmer
Meadow Beauty
There are 3 components of
biodiversity
Variety of ecosystems
Prairies, Ponds, and tropical rain forests are all
ecosystems. Each one is different, with its own set of
species living in it.
Paines Prairie
Florida Sand hill Pond
Hoh Rain Forest
Which is more diverse?
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Which is more diverse?
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Which is more diverse?
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Which is more diverse?
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Which has more cultural
diversity?
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Which has more biodiversity?
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Which has more biodiversity?
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Biodiversity has Intrinsic Value
Intrinsic Value = Something that has value
in and of itself
Biodiversity also has utilitarian
Value
Utilitarian Value = the value something has as
a means to another’s end.
Utilitarian values include:
• Goods
• Services
• Information
What do we get from
biodiversity?
Oxygen
Food
Clean Water
Medicine
Aesthetics
Ideas
Should we be concerned about
biodiversity?
What we know:
The Earth is losing species at an alarming rate
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Some scientists estimate that as many as 3 species per
hour are going extinct and 20,000 extinctions occur each
year.
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when species of plants and animals go extinct, many
other species are affected.
Threats to biodiversity
Habitat destruction
Pollution
Species Introductions
Global Climate Change
Exploitation
Climate Change:
Fitting the pieces together
The topic of climate change is like a puzzle with
many different pieces—oceans, the atmosphere,
ecosystems, polar ice, natural and human influences.
Scientists have been working on this puzzle for more
than a century, and while there are still gaps in our
knowledge, most experts feel we have the puzzle is
complete enough to show that human activities are
having an adverse effect on our planet. This talks
looks at many of those puzzle pieces, the evidence
behind them, and the conclusions we can draw from
them.
Outline
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What changes climate?
Is it real?
How do we know?
Why should we care?
How sure are scientists?
What next—what can we do?
What changes climate?
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Changes in:
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Sun’s output
Earth’s orbit
Drifting continents
Volcanic eruptions
Greenhouse gases
Scientists have a good understanding of what has changed earth’s
climate in the past:
• Incoming solar radiation is the main climate driver. Its energy
output increased about 0.1% from 1750 to 1950, increasing
temperatures by 0.2°F (0.1°C) in the first part of the 20th century. But
since 1979, when we began taking measurements from space, the
data show no long-term change in total solar energy, even though
Earth has been warming.
• Repetitive cycles in Earth’s orbit that occur over tens of thousands
of years can influence the angle and timing of sunlight.
•In the distant past, drifting continents make a big difference in
climate over millions of years by changing ice caps at the poles and
by altering ocean currents, which transport heat and cold throughout
the ocean depths.
•Huge volcanic eruptions can cool Earth by injecting ash and tiny
particles into the stratosphere.
•Changes in the concentration of greenhouse gases, which occur
both naturally and as a result of human activities, also influence
Earth’s climate
“Greenhouse
Increasing greenhouse
gases trap moreeffect”
heat
Greenhouse gases
Nitrous oxide
Carbon dioxide
Methane
Water
Sulfur hexafluoride
CO2 comes from a variety of sources. For example, plants take up carbon dioxide in
the air to make wood, stems, and leaves, and then release it back into the air when the
leaves fall or the plants die. The concern today is that fossil fuel use is putting huge
amounts of CO2 in the atmosphere at a rate faster than the climate system can adapt
to.
Certainly, past temperatures past have been
higher (and lower) than today, and
CO2 concentrations have also varied. Large
global swings were probably caused by such
things as changes in Earth’s orbit, which changed
the distribution of sunlight over the planet. When
this caused warming, more CO2 and other
greenhouse gases were released, producing
additional warming.
Could the warming be natural?
Earth is getting warmer by virtually every measure
we know, and the temperature has been well above
normal for more than 25 years. Although increases
of 1.0-1.6°F (0.6-0.9°C) over the last century or so
may not sound very threatening, remember that’s a
global average. The warming is stronger over land
than over oceans and in the higher latitudes than in
the tropics.
Is it real?
Snow and ice reflect the sun’s energy back to
space. Without this white cover, more water can
evaporate into the atmosphere where it acts as a
greenhouse gas, and the ground absorbs more
heat. Snow and ice are melting at rates unseen for
thousands of years. In Glacier National Park, for
example, there were 150 glaciers in 1850. Today,
there are 26.
Effects: Snow and ice
Grinnell Glacier, Glacier National Park
1900 and 2008
More water vapor held by a warmer
atmosphere also leads to heavier
rains and more snowfall. Intense
precipitation over the U.S. has
increased 20% over the last century.
Effects on precipitation
Increased warmth has also affected living
things. For example, the Japanese keep
very detailed records on the blossoming of
their Tokyo cherry trees, so they know they
are blooming 5 days earlier on average than
they were 50 years ago.
Effects on ecosystems
Scientists learn about the past
climate conditions from such things
as tree ring analysis, fossil
evidence, and analysis of patterns
and chemical composition in coral
skeletons and ice cores.
How do we know?
Present day observations
We know about the present
changes from observations taken
at the surface and in the
atmosphere.
[Image 1] The main tool for both past and present climate analyses are computer
climate models. Much like the models used to forecast weather, climate models
simulate the climate system with a 3-dimensional grid that extends through the land,
ocean, and atmosphere. The grid may have 10 to 60 different levels in the
atmosphere and surface grid spacings of about 60 by 90 miles (100 by 150 km)—the
size of Connecticut. The models perform trillions of calculations that describe
changes in many climate factors in the grid.
[click, Image 2] The models project possible climates based on
scenarios that cover a range of assumptions about global population,
greenhouse gas emissions, technologies, fuel sources, etc. The model
results provide a range of possible impacts based on these
assumptions.
Computer models
[Image 1] A common critique of climate predictions is, “If
weather model forecasts aren’t reliable more than a
week out, how can models predict climate decades in
the future?” While weather and climate models are
based on similar physics, they are not predicting the
same thing. Weather forecasts look at the day-to-day
changes on a local level, and subtle chaotic atmospheric
variations make short-term weather forecasts difficult
beyond 8-10 days.
[click, Image 2] Climate predictions are focused on
longer-term influences of the sun, oceans, land, and ice
on the atmosphere. Instead of predicting a temperature
at a particular place at a particular hour, climate modules
project an average temperature over a year or longer in
a large region or over the entire globe.
Aspen, CO Forecast:
Partly cloudy today
High : 28°F
Low: 13°F
Increasing clouds
over night. Colder
tomorrow.
Climate models are not only used to look at how climate might change, they’re also used to figure out WHY
it’s changing. When models are run with only natural influences from the sun and volcanic eruptions, they say
that during the latter half of the 20th century, we would have expected little change from normal conditions
(the blue line). Only the addition of human emissions (greenhouse gases, sulfates, and ozone) produce the
model results in red that most closely reproduce the black line of actual observations.
Why should we care?
Global average temperatures are expected to increase by about 2-13°F (1-7°C) by the end of the century. That
may not sound like a lot, so what’s the big deal? The problem is that small changes in global average
temperature can lead to really large changes in the environment. Let’s look at some of the expected changes.
[Image 1] There will always be natural variability, and
some places and some years will be warmer or cooler
than average. In general, however, summers will get
hotter, not only because of higher temperatures but
also because humidities will increase. That means that
heat waves, like the one that killed 35,000 people in
Europe in 2003, will become more common.
[click, Image 2] On the plus side, winters will be warmer
in many places, reducing heating bills. And the number
of days with frosts is likely to decrease.
U.K.: Train rails buckle
Germany: Lowest river levels
this century
France: >14,000
deaths
Switzerland: Melting
glaciers, avalanches
Portugal: Forest fires
2003 European Heat Wave
Sea-level rise projections : a few inches to a few feet
•2 ft: U.S. would lose 10,000 square miles
•3 ft: Would inundate Miami
•Affects erosion, loss of wetlands, freshwater supplies
•Half of the world’s population lives along coasts
•Big question: Ice sheets
The oceans will continue their rise in the coming century. The IPCC’s best estimates
range from a few inches to a few feet by 2100. If the rise is 2 feet, the US could lose
10,000 square miles, If they rise three, they will inundate Miami and most of coastal
Florida. Sea-level rise also increases coastal erosion and the loss of coastal wetlands,
and saltwater spoils freshwater drinking supplies. Coastal populations become even
more vulnerable to storm surge and flooding. Considering that half of the world’s
population lives near coasts, sea-level rise is a serious concern.
[Image 1] A warming planet means continuing changes
in its ecosystems. As the oceans absorb more carbon
dioxide, the chemistry of the ocean changes, putting
many sea creatures at risk. The IPCC projects that by
2100 the pH of the ocean will drop to its lowest point in
at least 20 million years.
[click, Image 2] As temperatures get milder,
mosquitoes, ticks, rodents, and other disease carriers
will expand their range, particularly in developing
countries. Here in the U.S., dengue hemorrhagic fever,
a tropical, mosquito-borne disease, hit for the first time
in modern times in 2005 in the Lower Rio Grande
Valley.
How sure are scientists?
What don’t we know?
• Is there some critical piece of the about climate process we don’t
understand?
• How and when will our fossil fuel use change?
• Will future , yet-to-be-discovered technologies mitigate the problem?
• How will changing economics, global population, and political processes
affect our ability to tackle the problem?
Nothing in science is 100% certain
There are no laboratory experiments that can tell us what the
future will be—the planet IS the test tube
What don’t we know?
• Is there some climate process we don’t know about? So far,
research over the years has strengthened the conclusion that
humans are adversely influencing climate, but scientific
knowledge is still evolving
We don’t know how things might change in the future, such as
• Will alternative energy sources become widely available? How
soon?
• Will some yet-to-be-discovered technology be able to clean
CO2 out of the air?
• How will changing economics, global population, and political
processes affect our ability to tackle the problem?
[Image 1] The International Panel on Climate Change, the
group that produces the main reports on climate change, is
a scientific intergovernmental body set up by the World
Meteorological Organization (WMO) and by the United
Nations Environment Programme in 1988.
[click, Image 2] The IPCC process involves hundreds of
scientists from about 140 countries, a variety of fields, and a
range of views. Their function is to assess the latest peerreviewed literature, [click Image 3] compare different
computer model results from various sources, and to
achieve consensus about where the weight of the evidence
points and where uncertainties lie. And
The IPCC
Based on the evidence accumulated over the last 40
years, these are some of their main conclusions. The
words in red were very carefully chosen to reflect
quantifiable estimates. So Very High Confidence and
means the statement has at least a 9 out of 10
chance of being correct, Very Likely means the
scientists are more than 90% sure, and Likely
means they are more than 66% sure.
2007 Conclusions
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Warming of the climate system is unequivocal
Very high confidence that global average net effect of
human activities since 1750 one of warming
Human-caused warming over last 30 years has likely had
a visible influence on many physical and biological
systems
Continued GHG emissions at or above current rates
would cause further warming and induce many changes in
the global climate system during the 21st century that
would very likely be larger than those observed during
the 20th century.”
Consensus?
• Do we know enough about the
drivers of climate to know what
causes change?
• Are we underestimating the Earth
system’s complexity ?
• Can models accurately simulate
the complex climate system?
•Are there processes that will limit
warming naturally?
On the other hand…
• Arctic sea ice melting faster than predicted.
• Fossil fuel emissions exceeded most IPCC
projections.
• Are assumptions about global energy use are
too optimistic?
•How quickly can developing countries reduce
GHG emissions?
• Calculations don’t include unexpected melting
in Greenland and Antarctica.
What do climate scientists really think?
Be an educated consumer
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IPCC AR4 Synthesis Report
(http://www.ipcc.ch/ipccreports/ar4-syr.htm)
Other organizations:
 NAS (http://dels.nas.edu/climatechange/)
 US CCSP (http://www.climatescience.gov/)
Look for contrasting opinions
Evaluate the source
Reducing our greenhouse gas emissions and our use of fossil fuels
will not be easy, but it is doable. Here’s how some researchers at
Princeton view it.
Our current path is toward doubling CO2 emissions in the next 50
years, with even greater increases beyond that. In order to get off this
path, we need to find ways to keep [8] emissions constant for the next
50 years and then reduce them during the second half of the century.
This would [9] limit atmospheric CO2 to about 570 ppm—still greater
than the roughly 380 ppm in the atmosphere today, but enough to
avoid the worst predicted consequences.
In order to hold carbon emissions constant over the next 50 years, we
need to find some combination of ways to cut 8 billion tons of carbon
emissions per year. In the graph, the difference between where we are
and where we’d like to be forms a triangle with a height of 8 billion tons
in 2055.
What next—what can we do?
What next—what can we do?
Produce more fuel-efficient vehicles
Reduce vehicle use
Improve energy-efficiency in buildings
Develop carbon capture and storage processes
Triple nuclear power
Increase solar power
Decrease deforestation/plant forests
Improve soil carbon management strategies
Here are examples of 8 technologies that could save 8 billion tons, or 8 wedges, of
carbon. Some of these we could do right away, while others are based on
technologies still being studied, such as capturing and storing carbon.
[Details on strategies:
•Efficient vehicles: Double car fuel efficiency in 2055 from 30 miles per gallon
(mpg) to 60 mpg
•Reduced vehicle use: Halve the miles traveled by the world’s cars in 2055
•Efficient buildings: Cut emissions by 25% in all buildings
•CCS electricity: Capture and store carbon from 800 large coal power plants or
1600 large natural gas power plants
•Triple the world’s current nuclear capacity
•Solar electricity: Increase solar capacity 700 times
•Forest storage: Halve global deforestation and double forest planting in 50
years
•Soil storage: Apply carbon management strategies to all of the world’s farm
fields]
This list represents only some of the possible strategies, but choosing strategies
will not be easy. However, the longer we wait to reduce emissions, the higher the
target will need to be, and the more adaptation will be necessary. In 2004, when the
wedges concept was first introduced, the target was only 7 billion tons.
Individual actions
Use mass
transit, bike,
walk, roller
skate
Buy water-saving
appliances and
toilets; installing
low-flow shower
heads.
Tune up
your
furnace
Caulk,
weatherstrip,
insulate, and
replace old
windows
Unplug
appliances or
plug into a
power strip and
switch it off
Buy products
with a U.S. EPA
Energy Star
label
Video
How Does Everything Fit?
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Click the image to play the video segment.