# Wednesday, April 11, 2012 Lecture 25

• Readings: Geo-Engineering – Oxford Companion to Global Change
• Climate “tech fixes” … - BBC News

The Ecological Footprint
• Look and see where we can adjust things to make the environment better
• Carrying Capacity: how many people can the planet support?
• How many planets do humans need?
• Everything we need to survive comes from solar energy and things on Earth
• Closed system, we are not bringing anything in
• How much land and water do humans need to: Dispose of waste, Survive
• Footprint can be estimated at multiple scales: global, national, cities, personal
• Can easily compare across people, cities, and nations
• Can observe the changes through time
• Simple concept, easily conveyed to the public

How much land is there?
• 22% of the Earth’s surface is useful and productive
• 4% biologically productive ocean (fisheries)
• 18% biologically productive land (forestry, croplands, grazing)
• 67% non-productive ocean
• If distributed equally amount 6 billion people: 1.8 global hectares/person (food, energy, all of waste) to be sustainable and not dramatically change the Earth’s systems

How much land do we use?
o Amount of land for us to live in houses/buildings
o Wetlands for waste absorption to clean water and landfills
o Space in the ocean and land to grow food (crops)
o Building materials and fires
o Oceans to absorb carbon from burning fossil fuels

What is our footprint?
o Humanity’s ecological footprint, 1961-2003
o 1963: using 50%
o 1980s: using 100%
o After 1980, over the biocapacity (over 100%)
o Can be over 100% because we are using non-renewable resources (carbon)
o Carbon is absorbed by the environment
o Many people in the world who do not eat enough and if they did there would not be enough food to go around
o More built-up and, nuclear energy, fishing ground, forest, grazing land, cropland all mostly the same (amount around the same, used our land more intensely/effectively)
o But CO2 from fossil fuels has doubled
o Ecological footprint per person, by country (2003): Most is the United Emerates, USA, Canada, Europian countries

Who are the debters and who are the crediters?
o Canada: rich in bio-capacity and natural resources
o All of the non-northern developed countries (excludes Scandinavia, Russia, Canada)
o Latin America has not exceeded their bio-capacity
o A lot depends on density
o Ecological footprint of international trade
o Figure out your own footprint: http://www.footprintnetwork.org/en/

Priority Actions for Consumers
o Transportation
o Food
o Household operations (air conditioning, lights, ect)
o Air travel

Earth: The Operators Manual
o Recap of course material
o Excellent selection of solutions
o Exam questions based on film!

Film Notes
o Climate change + Energy
o Growing population needs more and more clean energy

Chapter 1: Humans and Energy
o Began with fire, mostly fossil fuels
o 7 billion, headed to 10 billion
o Coal, oil, natural gas: 70%
o Nuclear: 5%
o Hydro: 6%
o Solar, wind, geothermal: 1%
o Wood and dung: 10%
o 1.5 billion without electricity or clean fuels
o 350 million Chinese move from country to city
o More people will use more energy as they escape from poverty
o Off the grid: a few hundred watts (a few bulbs), South America: 13, China: 22, Europe: 5000 watts, 50 bulbs, North Americans: 10000 watts, 100 bulbs
o If everyone started using energy like North American’s do, the world energy use would more than quadruple
o Burning through fossil fuels more than a billion times faster than they can be made
o Vary what goes into the Earth’s core and temperature and you get different fossil fuels
o Few hundred million years to form fossil fuels
o Reversing the process by which the fossil fuels formed (C + O2 = CO2)
o US Airforce needed to discover atmosphere for heat seeking missiles
o Smart missiles couldn’t see very far if they used a wavelength that CO2 absorbed
o Showed the heat-trapping influence of CO2
o Didn’t seek out global warming but CO2 turns up the planet’s thermostat
o Remove CO2, and things cool down
o Southern Alps: Glaciers (slow-moving rivers of ice sitting on land), used to be liquid water in the sea
o Brightness of the sun hasn’t changed, orbit changes (obliquity, eccentricity, precession)
o Changing currents let the oceans absorb CO2 from the air, cooled southern hemisphere and made glaciers
o Lower CO2, colder temperatures, Franz Joseph advanced
o Warming and cooling effects of rising and falling levels of CO2 to explain cooling (ice age)
o Atmosphereic CO2 is increasing, temperature is rising, glaciers are melting (today)

o Oldest core goes back 400 000 years, reveals earth’s climate history
o Can count when water turns to ice and can count (summer, winter, summer, winter)
o Ash of an Icelandic volcano that blew up to Greenland 50 000 years ago
o Bubbles form as snow turn to ice and trapped old air
o Cores from Antartica that are even older
o Tell us how much CO2 was in the air by analyzing gases that come off
o Pattern of rising and falling temperature along with CO2 levels are very related (180, 280 ppm)
o Can’t explain large changes in temperature without CO2
o In just 250 years (since Industrial Revolution) we have blown past 380 ppm, level not seen in more than 400 000 years (40x longer than oldest human civilization)
o How do we know that it is not just more natural variation? How do we know humans are the source of CO2?
o Is it because of the volcanoes? Humans are putting out 50- 100 times more CO2 than the volcanic sources
o Volcanoes don’t burn or use oxygen, melt rocks
o Humans burning: rise in CO2 comes with a decrease in oxygen
o C-12 (plants), C-13 (volcanoes), C-14 (radioactive, decays in 50 000 years, not in dinosaur bones or fossil fuels)
o See a rise in C-12 so the CO2 is not coming from volcanoes or recently living plants
o Climate change is certain, but what is it going to be like in specific regions of the world and when???
o Sea-level rise will be long-term and significant issue in the 21st century

o USA Army: Energy-Saving Experimental Base
o Test portable solar power units, purify water to make it drinkable
o Want to minimize number of convoys using fuel and water
o Lots of people killed or wounded when bringing supplies
o The military’s use of renewable energy can save oil
o This is a culture change, the Military can influence others
o US Military is the largest energy user in the USA
o China is the largest energy user on the Planet (population 4x larger)
o Energy research and incentives for wind, solar, and other clean energy technologies
o China is throwing spaghetti on a wall
o Coal is generating over 70% of energy in China, uses more coal than any other nation on Earth

o Can low-carbon solutions give us enough energy?
o 15.7 terawatts of energy for all humans on the earth (15 700 000 000 000)
o Can we get to 15.7 terawatts using only renewable energy?
o Solar powers in the dessert will be 0.01% of the energy we need
o Sun delivers 173 000 W to top of earth’s atmosphere (11x more than human use)
o 400 mirrors point at tall tower to create steam
o deserts in southern US have enough energy to provide 80% of the energy for the whole world!
o NIGHT IS A PROBLEM!!!
o Transmission and storage currently being developed
o Rainfall feeds planets rivers, hydro power…water power!!!
o High voltage direct current transmission lines to minimize energy loss
o This shows that renewable energy can go the distance!
o Dams displace people, disrupt landscapes and animals
o Hydro: 1.9 TW
o Plantstions harvest cane for harvest of sugar (or corn) and produce ethanol
o Ethanol made from sugarcane is 7x more efficient than corn
o Almost all cars sold in brazil use “flex fuels” mix of gasoline and ethanol
o Using food for fuel raises questions in a hungry world
o Can biofuels be made from agricultural waste? Yes, we are trying to reduce the costs
o Biomass: 166 TW
o New Zealand: geisers and hot springs, geothermal power plants harvest heat and are used for 10% of New Zealand’s energy
o Geothermal: 44 TW
o Accessable hot rocks beneath USA contain enough energy to run country for 130 000 years
o Can provide “peaking power” at a moment’s notice
o Windmills!!! Texas to the Canadian border (2000 miles)
o In Texas there is 1600 windmills in one county
o Windmills helps pay taxes and the feed bill, ranchers and farmers call it mailbox money
o Each windmill generates $5000-$15000 per year for the farmer
o Off-shore wind farms
o Properly cited turbines can minimize problems with birds
o Efficiency can cut energy by 1/3 by 2030
o Next generation nuclear,
o In 2030: Fossil fuels 13%, renewable 66%, current the rest