Download Global Warming 2007

Global Warming 2007
With secondary data taken mostly
from the IPCC report February 2007
ADPA March 2007
Contents
The Greenhouse Effect
The Enhanced Greenhouse
Empirical Evidence
Deduction
Summary of Temperature Records
Greenhouse Gases
Models and Feedbacks
Predictions
ADPA March 2007
The Greenhouse Effect
The concept of the global greenhouse effect
was proposed in 1824 by Joseph Fourier.
It is a natural phenomenon associated with the
various green house gases (GHGs) in the
atmosphere, that trap heat radiation emitted
from the planet.
Carbon Dioxide, Methane and Water Vapour
are all naturally occuring GHGs that help to
keep the planet around 17 degrees warmer
than without.
ADPA March 2007
Enhanced Greenhouse Effect
Human activities release additional greenhouse
gases into the atmosphere – anthropogenic
source. It seems likely that this will increase the
power of the greenhouse – in other words cause
an “Enhanced Greenhouse Effect”.
This idea is not particularly new either first proposed
by British physicist John Tyndall in 1859. In the
1880’s Swedish physicist Svante Arrhenius
predicted that a doubling of Carbon Dioxide would
lead to a global temperature rise of 5 degrees
Celsius.
ADPA March 2007
Empirical Evidence




There is plenty of good empirical evidence for
all of the following.
Anthropogenic GHG emissions have
increased and continue to increase.
Due to the warming GHG emissions are
increasing from a number of sources
Temperatures are rising rapidly.
ADPA March 2007
Deduction and Debate


It is a matter of scientific deduction as to whether
anthropogenic emissions are causing global
warming, and consequently it is an area of debate
amongst scientists and politicians.
The IPCC report stated: “Most of the observed
increase in globally averaged temperatures
since the mid-20th century is very likely due to
the observed increase in anthropogenic
greenhouse gas concentrations.”
ADPA March 2007
Is the word getting hotter?
Evidence from historical records back over the last 100
years and from ice cores that record temperature
over the last 650,000 years (four glacial/interglacial
cycles) show that we are currently experiencing a
hotter average temperature.
Eleven of the last twelve years (1995 -2006) rank
among the 12 warmest years in the instrumental
record of global surface temperature (since 1850).
ADPA March 2007
Historical Records
Line – Decade Average
Circles – Yearly
Shaded Area – Margins of Uncertainty
ADPA March 2007
Ice Core Data
ADPA March 2007
Foramiferan Indicator Species Data
This figure shows the climate record of Lisiecki and Raymo (2005) [1]
constructed by combining measurements from 57 globally distributed
deep sea sediment cores. The measured quantity is oxygen isotope
fractionation in benthic foraminifera, which serves as a proxy for the
total global mass of glacial ice sheets.
ADPA March 2007
Models
Climate Scientists use complex computer
models to generate predictions on warming.
One complication are the large number of both
positive and negative feedbacks in that
influence climate.
ADPA March 2007
Negative Feedbacks
Feedbacks in the global ecosystem can be
negative, leading to a controling effect and an
amelioration of warming. For example the
warming is predicted to increase precipitation
in polar areas as snow, increasing albedo
(reflectivity of surface) leading to a cooling
effect.
ADPA March 2007
Positive Feebacks
There are many positive feedbacks that may
increase warming, possibly resulting in a
runaway greenhouse.
For example the solubility of Carbon Dioxide in
sea water decreases with increasing
temperature leading more to be released and
further increasing the temperatures.
ADPA March 2007
Feedbacks – are these positive or negative?
1.
2.
3.
4.
5.
Thawing of permafrost leads to a release of methane from
waterlogged soils.
Rate of photosynthesis in plants increases more carbon
dioxide is therefore removed from the atmosphere.
Ice cover melts, exposing soil or water and albedo decreases
Increased evaporation produces more clouds increase
tropospheric albedo, reflecting more light away from Earth
As Earth warms, organic matter in soil is decomposed faster
more carbon dioxide is released
ADPA March 2007
Runaway Greenhouse Effect
This has been a suggestion since the earlier
work of the IPCC. Scientists such as Steven
Schneider hypothesised that we may pass a
tipping point when positive feedbacks in the
greenhouse effect become more powerful
than the negative. This would lead to an
accelerating warming and could give the
Earth a Venusian climate system on a short
time scale.
ADPA March 2007
Summary of GHG Changes

Global atmospheric concentrations of carbon dioxide,
methane and nitrous oxide have increased markedly as a
result of human activities since 1750 and now far exceed preindustrial values determined from ice cores spanning many
thousands of years.

Direct measurements of carbon dioxide since the 1960’s at
Mauna Loa in Hawaii show a steady increase to the present
day.

The global increases in carbon dioxide concentration are
due primarily to fossil fuel use and land-use change, while
those of methane and nitrous oxide are primarily due to
agriculture.
ADPA March 2007
GHG Sources, Warming Potential and
Significance
Gases and Source
Significance
Carbon Dioxide from any combustion,
decomposition or respiration.
No. 1 cause of Global Warming
GW Potential 1, Atmospheric concentration –
360ppm and increasing rapidly
Methane from anaerobic respiration and
decomposition in rice fields swamps.
Landfill sites and flatulent cows.
No. 2 cause of Global Warming
GW Potential 21, atmospheric concentration 1.72ppm – major stores under arctic
permafrost.
Nitrogen Oxides formed from atmospheric
nitrogen in the internal combustion
engines.
No. 3 cause, GW Potential = 206.
Atmospheric concentration= 0.31
Chlorofluorocarbons (CFCs) from fridge
coolants and aerosol cans.
Most potent greenhouse gas per molecule GWP
= 3500-7000 times carbon dioxide, but due
to low levels less significant than the other
gases. Also depletes ozone in stratosphere
ADPA March 2007
Carbon Dioxide - The Last 10,000 years
Measurements
are shown
from ice cores
(symbols with
different
colours for
different
studies) and
atmospheric
samples
(red lines).
ADPA March 2007
Mauna Loa
Carbon Dioxide Measurements
ADPA March 2007
Methane the Last 10,000 years
Measurements
are shown
from ice cores
(symbols with
different
colours for
different
studies) and
atmospheric
samples
(red lines).
ADPA March 2007
Nitrous Oxide the Last 10,000 years
Measurements
are shown
from ice cores
(symbols with
different
colours for
different
studies) and
atmospheric
samples
(red lines).
ADPA March 2007
Carbon Dioxide

Carbon dioxide is the most important anthropogenic greenhouse
gas. The global atmospheric concentration of carbon dioxide has
increased from a pre-industrial value of about 280 ppm to 379 ppm
in 2005. The atmospheric concentration of carbon dioxide in
2005 exceeds by far the natural range over the last 650,000 years
(180 to 300 ppm) as determined from ice cores. The annual
carbondioxide concentration growth-rate was larger during the
last 10 years (1995 – 2005 average: 1.9 ppm per year), than it
has been since the beginning of continuous direct atmospheric
measurements (1960–2005) average: 1.4 ppm per year)
although there is year-to-year variability in growth rates.
ADPA March 2007
Predictions
The following slides show a series of graphs
and maps that predict climate change against
a number of scenarios described in the slides
at the end of the presentation.
ADPA March 2007
IPCC
Scenarios
A1
A1B
A2
B1
ADPA March 2007
Predicted
Warming against
the IPCC
Scenarios
B1
A1T
B2
A1B
A2
A1F1
ADPA March 2007
Isotherm Maps of Predicted Warming
ADPA March 2007
ADPA March 2007
The Emission Scenarios of the IPCC Special
Report on Emission Scenarios
An illustrative scenario was chosen for each of the six
scenario groups A1B, A1FI, A1T, A2, B1 and B2. All
should be considered equally sound.
The SRES scenarios do not include additional climate
initiatives, which means that no scenarios are
included that explicitly assume implementation of
the United Nations Framework Convention on
Climate Change or the emissions targets of the
Kyoto Protocol.
ADPA March 2007
A1 Family of Scenarios
The A1 scenario family develops into three groups that
describe alternative directions of technological
change in the energy system. The three A1 groups
are distinguished by their technological emphasis:
fossil intensive (A1FI), non-fossil energy sources
(A1T), or a balance across all sources (A1B) (where
balanced is defined as not relying too heavily on one
particular energy source, on the assumption that
similar improvement rates apply to all energy supply
and end use technologies).
Back to First Graph
ADPA March 2007
A1

A1 a future world of very rapid economic growth,
global population that peaks in mid-century and
declines thereafter, and the rapid introduction of new
and more efficient technologies.

Major underlying themes are convergence among
regions, capacity building and increased cultural and
social interactions, with a substantial reduction in
regional differences in per capita income.
Back to First Graph
ADPA March 2007
A2.

The A2 storyline and scenario family describes a
very heterogeneous world. The underlying theme is
self reliance and preservation of local identities.
Fertility patterns across regions converge very
slowly, which results in continuously increasing
population. Economic development is primarily
regionally oriented and per capita economic growth
and technological change more fragmented and
slower than other storylines.
Back to First Graph
ADPA March 2007
B1

The B1 storyline and scenario family describes a
convergent world with the same global population,
that peaks in mid-century and declines thereafter, as
in the A1 storyline, but with rapid change in
economic structures toward a service and
information economy, with reductions in material
intensity and the introduction of clean and resource
efficient technologies. The emphasis is on global
solutions to economic, social and environmental
sustainability, including improved equity, but without
additional climate initiatives.
Back to First Graph
ADPA March 2007
B2

The B2 storyline and scenario family describes a
world in which the emphasis is on local solutions to
economic, social and environmental sustainability. It
is a world with continuously increasing global
population, at a rate lower than A2, intermediate
levels of economic development, and less rapid and
more diverse technological change than in the B1
and A1 storylines. While the scenario is also
oriented towards environmental protection and
social equity, it focuses on local and regional levels.
Back to First Graph
ADPA March 2007
The Consequences of Global Warming





Cause biomes to shift their distribution patterns
(How could this occur with fragmented, isolated
habitats moving across urban areas, agricultural
systems, transport networks? Could it happen at the
speeds of temperature change given?)
Change the location of crop growing areas (what
would be the geopolitical consequences of this?)
Change Weather Patterns (Cyclones increase in
frequency and intensity)
Cause Coastal Flooding ( Predicted sea level rise
would swamp low-lying areas)
Cause a change in the distribution of diseases
limited by temperature (Such as Malaria)
ADPA March 2007
Further Reading
http://www.ipcc.ch/
http://www.unep.org/
http://www.climatecrisis.net/
www.funnyweather.org
ADPA March 2007