GLOBAL WARMING

Just the facts.

Making Connections We are discussing global warming for 2

reasons:

1.There is evidence that increasing [CO2] is a factor in the apparently increase in global temperatures

2.Plants play an extremely important role in the drama called ‘global warming’ - (plants... photosynthesis... CO2... get it?)

What is global warming? The apparent increase in average temperature all

over the world about 0.8oC since the late 1800s (agreed upon by

600-700 balloon stations, satellites, and surface measurements) Where does this come from?

THE GREENHOUSE EFFECT

Why do we care? Changes have been: Unprecedented Rapid Irreversible

THE GREENHOUSE EFFECT

Greenhouse Gases (GHG’s)NATURAL GHG’s CO2 – carbon dioxide

H2O(g) – water vapor

CH4 - Methane

N2O – Nitrous oxide

O3 – Ozone

ARTIFICIAL CFC - chlorofluorocarbons HCFC – hydrochloroflurocarbons HFC - hydroflurocarbons

Effect of Greenhouse Gases (GHG’s)DIRECT: Absorb reflected IR radiation, thus the energy

(heat) it carries remains in the atmosphere

INDIRECT: Emit non-GHG such as CO, NOx, etc that react

chemically to create O3 or extend the lifetime of GHGs

BOTH! CH4 is a GHG but also affects the amount of other GHGs in the atmosphere (atmospheric chemistry)

Effect of Greenhouse Gases (GHG’s)Lets break down the GHGs

1. N2O – Nitrous oxide

**levels have climbed from 275ppbv – 315ppbvSources:

Nitrogen fertilizers on soils Biomass/fossil fuel burning Lightning Natural Fires Oceans

Life span: 120 years!

Sinks: Photochemical destruction in the stratosphere by UV

Effect of Greenhouse Gases (GHG’s)Lets break down the GHGs 2. O3 – Ozone (there are 2 types: stratospheric and

tropospheric)* tropospheric levels have doubled from 10-15ppbv – 20-

30ppbv**levels are as high as 100ppbv in polluted citiesSources:

Not directly released butproduced from rxn’s of other hydrocarbons: CH4

NOx, CO

Life span: a few weeks!

Sinks: Chemical reactions in the atmosphere

**Due to this short life span we COULD regain the full ability of the ozone layer in 50 years**

Effect of Greenhouse Gases (GHG’s)So what’s the real deal with the Ozone...The stratosphere is where ‘ozone hole’ is located:• There is not a hole in the ozone layer, it’s just a

thinning of the stratosphere in above the poles (especially Antarctica) • This allows more UV-B rays to reach the earth’s surface

• Increased UV radiation can lead to:• Increased incidences of skin cancer

and cataracts• weakened immune response• decreased crop yield

• (UV-B affects cyanobacteria in roots)

Effect of Greenhouse Gases (GHG’s)What are the main causes for ozone layer depletion? CFCs (and the family of HCFCs, HFCs, etc)

Contain chlorine and bromine which are able to break down O3

This occurs more rapidly at colder temperatures CO2

Decreases temp of stratosphere, thusincreasing affect of CFCs

CH4

Oxidation of CH4 in the stratosphereto form OH- which reacts with HCl to release harmful Cl- ions

Effect of Greenhouse Gases (GHG’s)Lets break down the GHGs... 3. CH4 – Methane

**levels have climbed from 0.700ppmv – 1.725ppmv (~150%)

Effect of Greenhouse Gases (GHG’s)Lets break down the GHGs... 2. CH4 – Methane

Sources: Ruminant animals Manure rice paddies landfills/sewage treatment biomass burning coal mine seepage natural gas venting in oil operations

Life span: 8 years!

Sinks: 85% - Conversion by OH- to form CO2 andH20

15% - Absorbed by soils

Effect of Greenhouse Gases (GHG’s)Lets break down the GHGs... 4. CO2 – Carbon Dioxide

Sources: Fossil fuel burning (7Gt) [Gt = gigatons = 109 ] Deforestation (2Gt) Decay of plant and animal matter, respiration of plants and animals = 100 Gt/yr

but is almost perfectly balanced by photosynthesis (for now!!).

Also, gaseous outflows from oceans but is almost perfectly balanced by gaseous inflow

under constant climate

Effect of Greenhouse Gases (GHG’s)Lets break down the GHGs... 4. CO2 – Carbon Dioxide

Sinks: 60% is absorbed by oceans and land plants for now, all but 10-20% of what we have

emitted so far will eventually be absorbed by oceans

After several 1000 years, all but 5-10% will be absorbed by oceans (as CaCO3 on the ocean floor will dissolve)

*Life span: Depends, it may be within a matter of years or

100,000 years!

Effect of Greenhouse Gases (GHG’s)Lets break down the GHGs... 5. CFCs – Chlorofluorocarbons (& family)*ZERO natural concentration, a rapid increase in [x] after 1960

**[CFC] has started to decrease due to phase out of products, WHILE

Sources: Entirely human.

Used in refrigeration, air conditioning, and cleaning electrical equipment

Sinks: Photochemical destruction in the stratosphere, Destruction of HCFCs/HFCs in troposphere by OH-

*Life span: 50,000 years for CFCs, 1-10 years for HCFCs, 10-100 years for HFCs!

So what’s the deal with CO2?

Water vapour – H2O(g) – is actually the most prevalent GHG But, CO2 is much more potent in increasing the

greenhouse effect

Effects of CO2

Effects of CO2

Mid-latitude Tornadoes - May become more destructive as climate warms (but very uncertain). - Most likely they will become regionally depending on the ocean temperature and wind shear.

TsunamisWhen the ice is lost, the earth's crust bounces back up again and that triggers earthquakes, which trigger submarine landslides, which cause tsunamis

Effects of CO2 (positive feedback)Increasing CO2 --> warmer climate -->

partial drying of saturated Arctic soils --> respiration of peat --> more CO2 to atm

forests can't adapt and die back --> further increase CO2 to atm

thawing of land and continental shelf permafrost in arctic --> further warming of climate

ice and snow melt back --> less albedo --> more solar energy absorbed (less reflected back out) --> further warming

more sluggish ocean circulation (less wind) --> reduced marine activity due to less upswelling of nutrients --> higher CO2 to atm

Direct CO2 effect on agriculture 1) Increased water use efficiency by plants• CO2 enters plant through stomata on bottom of leaves and depends on: a) number and size of stomata openings and b) difference in [CO2] inside and outside leaf

• Increasing CO2 outside of leaf will increase the concentration gradient and cause the openings to not open as much to take in as much CO2 for photosynthesis.

• Narrower stomata inhibit the loss of water and thus an increase in water use efficiency

2) Increases photosynthetic rate • C3 plants depend on the balance between gross photosynthesis and

photorespiration• both processes use the enzyme Rubisco

• If more CO2 is present than O2, then CO2 will outcompete O2 for binding sites and photosynthesis is favoured (this will occur even if light is a limiting factor)

3) Ecological Considerations • Earlier flowering may occur, thus insect pollinators could be important

(migration rates)• Decrease in litter quality, which reduces rates of decomposition• Decrease of forage quality, thus herbivores will have to eat more to get

the same amount of nutrients

Indirect CO2 effect on agriculture 1) Temp increase will be beneficial for agriculture in regions near cold-

limits but will be detrimental for: A) crops that already suffer heat stress B) grain crops where a decrease in the length of time to maturation yields

less grain products C) poor developing countries D) tropics, as corn yields fall with any amount of warming, E) rice yields rise for a 1o warming (but drop after that)

2) Precipitation – increase in average rainfall will affect:A) Individual events: if occur as fewer but more intense downpours, more

of the rain will be lost as runoff and average soil moisture will decrease. B) Seasonal distribution: an increase in rainfall in a dry region all occurring

at the beginning of the growing season, or when grain should be ripening, isn't much good

3) Evaporation and Soil Moisture • A warming climate will increase evaporation, thus precipitation must

increase simply to maintain present soil moisture • if precipitation doesn't increase enough, soil moisture will decrease

DEFORESTATIONSimply put...

• Plants (or trees) are a HUGE sink for CO2

• By clear cutting forests, we are losing these CO2 sinks, thus increasing CO2 in the atmosphere

• Sadly, underdeveloped countries cannot protect their forests so underground logging operations are clear cutting everything they can

How can we overcome deforestation?1. End Deforestation - requires making more efficient use of forest products (more

efficient wood burning stoves)- using agricultural land more efficiently so that less land is needed

for food production

2. Reforestation - net carbon removal only occurs while trees are growing. - once the forest has reached its maturity, it must be maintained or

the carbon will go back to the atmosphere - leaving no net benefit - reforesting land that is not suitable for agriculture could absorb 1-

2Gt C/year for several decades- *combined with deforestation this could surely stabilize

atmospheric CO2 while we work on fossil fuel emissions

*REFORESTATION COSTS MONEY!!! (what is the country going to get out of it?)

How can we overcome deforestation?3. Biomass Energy (wood, straw, biological waste products such as

manure)- used as an energy source to displace coal and other fossil fuels. - The net carbon benefit of using land for biomass energy is greater

than using the same land for permanent carbon storage

4. Enhanced growth of existing forests - using forests as a sink to partially offset CO2 emissions requires

1) that those emissions themselves are falling so that the degree and rate of climatic change are kept as small as possible

2) that other stress on forests (acid rain and ozone) are diminished as quickly as possible, which also implies reduced use of fossil fuel

SEA LEVEL RISE (SLR)!So far: 1.8mm per year for the last century (1.8mm x 100 = 180mm

= 18cm)*Studies suggest that 2.8mm – 3.1mm per year in the last decades

Predictions: typically range from 90 to 880 mm over next 100 years

Regional Impacts of SLR • Coastal wetlands• coral reefs• estuaries

Physical Impacts of SLR • flooding of coastal regions, • impacts on islands, • coastal erosion, • salt water intrusion, • interactions with rivers• flooding of waste facilities• change in storm frequency

SEA LEVEL RISE!Coral Reef Issues• Bleaching (coral needs to be at specific depth below water level

so that bacteria can use sunlight)• Decreased Carbonate saturation• increased attacks by disease organisms

Marine Biological Productivity• Reduced nutrient upwelling from ocean depths • heat stress, • reduced carbonate supersaturation, • increased acidity of water (carbonic acid)

5 Ways to Reduce CO21) Improve the efficiency in converting from 1o to 2o energy by:

a) generating electricity more efficiently from fossil fuels than at present and b) reducing the energy losses in the production of refined gas productions from oil

2) Improve the efficiency in converting from 2o to 3o energy by more efficient: a) use of electricity (in motors, appliances, and lighting) and b) automobiles and aircrafts

3) Reducing the demand for end use (3o) energy: a) design cities that have shorter travelling distances and that have transit systems that promote walking, biking, or public transit; b) increase recycling of energy-intensive materials (steel and aluminum); c) design building that less heat is lost in winter (less cooling in summer); d) modify people's behaviour to be more climate conscious

5 Ways to Reduce CO24) Switching the mix of energy sources used:

a) switching from coal to oil to natural gas within the fossil fuel portion of the energy supply mix; b) switch from electricity to direct use of natural gas for space and water heating (especially when coal is used); c) switching from fossil fuels to renewable forms of energy wherever possible (such as solar, wind, biomass, and geothermal energy)

5) Capturing CO2 produced from the combustion of fossil fuels: - before it is released to the atmosphere, and permanently disposing of it in deep geological strata or in the deep ocean

Alternative EnergyWind: fastest growing source of energy of electricity generation in

the world in the last 20 years, but is still a small fraction of electrical generation

• Wind turbines typically convert 25% of the kinetic energy of the wind that crosses the rotor to electricity

• Worldwide installed capacity by the end of 2006 was almost 75GW (compared to the 3300GW used world wide)

• North Dakota alone could generate electricity to total US consumption BUT problems:

a) some of the best wind resources are not close to major demand centres

b) the wind does not blow all the time, a minimum windspeed of 3-4m/s is needed before the turbine will produce any electricity at all

Alternative EnergySolar: 0.6% of the world's deserts surface is an area of

66,000km2, whereas the cumulative worldwide production of PV modules only covers 25km2

PROBLEMS:

a) most of the electricity demand is not close to sunny deserts

b) the sun doesn't always shine

Alternative EnergyHydro-electric: 0.2 TW worldwide with potential of 1.1TW. • Most have to be left undeveloped to protect biological heritage

regions and to respect native land rights • Does not need to be a big operation, a lot can be obtained from

many small-scale river plants that would have much less environmental and social impact

Geothermal: Water is pumped down holes drilled into deep rock, is heat, then rises through other holes and is used to generate electricity.

• Worldwide capacity is 10GW

Nuclear: hard to justify until determine where waste can go for 10,000yrs or more.

• More expensive which would worsen the greenhouse problem by taking away funds from more worthwhile investments

Alternative EnergyHydrogen

1. Usable in all the end-use applications where Fossil Fuels are currently used 2. Non-polluting 3. Storable (this is a problem limits electricity produced from renewable but intermittent energy sources such as solar, wind, tidal, or hydro-electric) 4. Portable (especially important for transportation energy use) 5. Safe 6. Efficient 7. Affordable 8. Capable of stimulating development of new technologies

FINALLY, WHAT YOU CAN DO!Windows of Opportunity

• The biggest opportunity to reduce energy use and incorporate renewable energy involves new buildings.

• Once they are built it becomes more difficult and costly to increase efficiency

• 1) compact flurorecent light bulbs (CFLs) now cost about $3-4 each and can replace just about any use of incandescent light bulbs. • They use 4-5x less energy

• 2) The best front-loading clothes washer uses about 5x less energy than the typical top-loading machine. • They also save energy because less detergent is needed. • Also, the clothes come out with half the water on them thus less need

for a increased drying time • 3) The latest fridges use about 1/4 the electricity vs. older models,

FINALLY, WHAT YOU CAN DO!Windows of Opportunity1) To design building with

- High degrees of insulation- quality construction that eliminates air leakage, - high-performance windows (triple-glazed windows

have 1/3 heat loss of a conventional double-glazed window!) - adjustable external shading devices - It has been consistently shown that space-heating requirements can be

reduced by a factor of 4-10

2) To satisfy as much of the remaining energy demand through passive solar energy features as possible:- Lighting during daylight hours can be largely met with natural light, - Buildings can be designed such that most of the ventilation

requirements can take advantage of winds and natural temp differences that drive ventilation flow.

- Wear a friggin’ sweater!

FINALLY, WHAT YOU CAN DO!Windows of Opportunity

3) Use the most efficient equipment and systems available to meet the remaining cooling, lighting and ventilation requirements. - incremental improvements to individual energy-using devices. Ex. Using more efficient pumps, fans, & air conditioners

4) Use active solar energy features to supply as much of the remaining energy demand as possible: - solar thermal collectors (water pipes attached to an absorbing surface, used to make hot water) - PV (photovoltaic) panels to generate electricity.