Transcript Document
Lecture 28 More effects of global warming and the first part of solutions Other problems •Droughts, floods and storms will worsen unless measures are taken to cut emissions in half by 2050 relative to 1990 levels. About 262 million people were affected by climate disasters from 2000 to 2004, most of them in developing countries. •Flooding from high tides and storm surges - will preferentially affect populations coastal and low-lying areas like river deltas - Nile in Egypt, Ganges and Brahmaputra in Bengladesh, Mekong in Vietnam. Over 70 million Bangladeshis, 22 million Vietnamese, and six million Egyptians could be affected. •More severe and possibly more frequent cyclones and hurricanes - you’d think Katrina would have been a wake up call. August 2005. Hurricane Katrina battering New Orleans. Katrina caused at least $125 billion in damages, by far the most ever by a hurricane. Much of the damage is still not repaired and many of the displaced people will likely never return. April 15, 2008 May 5, 2008 Other problems continued •The breakdown of agricultural systems as a result of increased exposure to drought, rising temperatures, and more erratic rainfall, leaving up to 600 million more people facing malnutrition. Semi-arid areas of subSaharan Africa with some of the highest concentrations of poverty in the world face the danger of potential productivity losses of 25% by 2060. Unequal Impacts Every year the UN Development Program issues a report on the status of developing nations. The 2007-2008 report, Fighting climate change: Human solidarity in a divided world, argues that global warming could lock the world’s poorest countries and their poorest citizens into a downward spiral, leaving hundreds of millions facing malnutrition, water scarcity, ecological threats, and a loss of livelihoods. The UNDP Administrator Kemal Derviş put it this way, “Ultimately, climate change is a threat to humanity as a whole. But it is the poor, a constituency with no responsibility for the ecological debt we are running up, who face the immediate and most severe human costs.” Where do we go from here? How do we fight global warming? The first priority has to be cutting back on fossil fuel burning Worldwide energy supply in TW World power usage and technologies now: 85% fossil fuels Only about 5-10% is renewable energy usage Cutting back on fossil fuels •First it’s important to say that these problems are solvable though they are large and extremely complex •Technologies to reduce CO2 emissions from burning fossil fuels and renewable energy technologies exist but will have to be enormously expanded to have much impact •Political will and leadership will be required - there will be painful costs and jarring changes to our accustomed ways of living •We must get started. James Hansen, the climate scientist at NASA who began 20 years ago to sound the alarm on global warming, thinks we have only 10 years to start cutting - not just slowing - the amount of carbon we emit or we will “face a different planet”. And he said this two years ago. So, eight years left. Cutting back on fossil fuels •Energy efficiency •Waste heat capture •Carbon capture and sequestration •Renewable energy replacements •Wind, solar, geothermal •Biomass •For transportation •Biofuels, hydrogen, electricity Energy efficiency: •This should be the “easy” part of reducing fossil fuel usage •At the same time that emissions are reduced, less energy is used so costs are reduced, either for businesses or individuals • Being efficient saves money and increases economic competitiveness Examples •More efficient lighting - CFLs •Better building or housing design •Better insulation •More efficient heating/cooling systems •Efficient appliances •Efficient autos Examples •More efficient lighting - CFLs •Better building or housing design •Better insulation Improving building efficiency •More efficient heating/cooling systems Since buildings account for about two thirds of all electricity used in the US, there are large opportunities for savings. Perhaps as much as 10-20% of total electricity use. Efficient appliances - Art Rosenberg LBNL •Refigerators and freezers consume about a sixth of all electricity in a typical American home - more than any other single household apppliance •Rosenberg, a physicist at LBNL, noticed this and succeeded in getting California to pass a series of tightening regulations for energy usage by refrigerators. •These regulations were fought and then embraced by appliance manufacturers. •Current refrigerators consume just a quarter as much electricity as a similar sized refrigerator 20 years ago. •This is a great model for other types of energy efficiency regulations. Efficient autos •Less than 1% of the energy used to move a car is required to move the passengers •Most of the rest is used to move the weight of the car, to fight wind resistance, and to overcome rolling resistance •There is a lot of room to reduce the weight of cars and therefore reduce the energy requirements. •New materials - lightweight metals and especially carbon fiber resins - can be not only light but also strong. There is an interesting slide show about super light hypercars on the Rocky Mountain Institute website (www.rmi.org) •Some of the prototypes can get >100 miles per gallon, even >200 mpg The Jevons Paradox This is a counter-intuitive observation that as technology increases the efficiency with which a resource is used, total consumption of that resource tends to increase, rather than decrease. In addition to reducing the amount needed for a given output, improved efficiency lowers the cost of using a resource – which increases demand. William Stanley Jevons For example, England's consumption of coal soared after James Watt introduced his coal-fired steam engine, greatly improving the efficiency of an earlier design. Watt's innovations made coal a more cost effective power source, leading to the increased use of the steam engine in a wide range of industries. This in turn increased total coal consumption, even as the amount of coal required for any particular application fell. Increased energy efficiency tends to increase energy consumption by two means. First, increased energy efficiency makes the use of energy relatively cheaper, thus encouraging increased use. Second, increased energy efficiency leads to increased economic growth, which pulls up energy use in the whole economy.