Climate Change - The Science • https://www.youtube.com/watch?v=DOAqECd70Ww • Energy travels through a vacuum between the sun and the earth by means of electromagnetic radiation or light. Objects can absorb energy from the light and can emit light energy[if the vibrations of their chemical bonds generate oscillations of the electrical field]. • The temperature of the surface of the earth is controlled by the ways that energy comes in from the sun and shines back out to space as infra-red. Sunlight strikes the earth and deposit some its energy on earth. The account of the energy that enters the earth and leaves the earth is known as the energy balance of the earth. • The earth’s energy budget is the net result of a complex balance of energy flows over time, and exerts a primary influence on global climate. Earths Energy Balance Energy Balance • Less than half of the incoming sunlight heats the earth. The rest is reflected away by white clouds/ice or gets absorbed by the atmosphere. The sunlight that makes it to the ground warms the earth surface. • Light from the sun is absorbed by land, water, and vegetation on the surface of the earth and give off infrared –which we feel as heat. The infrared radiation or heat moves back up through the atmosphere. • In the atmosphere, green house gases prevent the heat from leaving as fast as they came in. • .Green house gases in the earth’s atmosphere contains molecules that absorb this heat and reradiate the heat in all directions. These greenhouse gases have a molecular structure made up of more than two component atoms that are able to vibrate with the absorption of heat. • Eventually, a vibrating molecule emits the radiation again, which is often reabsorbed by yet another greenhouse gas molecule. The absorption-emission- absorption cycle that occurs among greenhouse gases effectively holds heat in the atmosphere near the earth’s surface, just as clear glass walls hold heat in a greenhouse, thereby slowing the process of heat being lost into space. Climate Change. • Without the greenhouse effect, the mean surface temperature of the earth would be about 33 degrees Celsius lower than it is today, and most of the world’s oceans would freeze over. • Greenhouse gas molecules are responsible for the fact that the earth enjoys temperatures suitable for life as we know it in our complex biosphere. • Examples of green house gases include carbon dioxide, various halocarbons, methane, nitrogen oxides, nonmethane volatile organic compounds such as benzene, ethanol; ozone, sulfur hexafluoride, and water vapor • Water vapor is the most abundant and dominant greenhouse gas in the atmosphere but due to the anthropogenic source and the rising concentration in the atmosphere, carbon dioxide receive more attention. Carbon Cycle • All living things are made of elements, the most abundant of which are, oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorous. • Of these, carbon is the best at joining with other elements to form compounds necessary for life, such as sugars, starches, fats, and proteins. Together, all these forms of carbon account for approximately half of the total dry mass of living things.- “carbon-based life forms”-Star Trek. • Carbon is also present in the Earth's atmosphere, soils, oceans, and crust. These components can be referred to as carbon pools (sometimes also called stocks or reservoirs) because they act as storage houses for large amounts of carbon. • Any movement of carbon between these reservoirs is called a flux. • In the earth system, fluxes connect reservoirs together to create cycles and feedbacks. An example of such a cycle is; carbon in the atmosphere is used in photosynthesis to create new plant material. This processes transfers large amounts of carbon from one pool (the atmosphere) to another (plants). Over time, these plants die and decay, are harvested by humans, or are burned (fossil fuels) either for energy or in wildfires. • Carbon cycle refers to the flow of carbon among the various reservoirs of carbon. • The carbon cycle plays a key role in regulating the Earth’s climate by controlling the concentration of carbon dioxide in the atmosphere Carbon Cycle Carbon Cycle • Atmospheric carbon dioxide levels have been measured continuously since 1958. Charles Keeling measurements produced what is referred to as the Keeling Curve. The keeling curve shows the change in CO2 content with time. The keeling curve show two interesting features: i. Every year CO2 concentration reaches a maximum in May and then decreases until October and then it begins to rise. This is due to cycle of plant growth and death in the northern hemisphere. ii. The second feature of the Keeling curve is that atmospheric CO2 content has been rising rapidly. • Approximately 3.3 of the 6.3 billion metric tons (gigatons) of anthropogenic carbon fail to be taken up by the other reservoirs each year, and add to the accumulated stock of carbon (and other greenhouse gases) in the atmosphere. • Every 2.1 gigatons of carbon-equivalent emissions (net of what is taken up by the earth’s carbon sinks) results in a 1 ppm (part per million) increase in atmospheric carbon dioxide concentrations. • It is this progressive rise in atmospheric greenhouse gas concentrations, caused by anthropogenic emissions in excess of the earth’s capacity for uptake and sequestration, that results in a climate forcing: Mechanism that alters the global energy balance Economics of Climate Change • The Problem: Climate change is a global public bad; market failure. Any action taken to moderate climate change provides a global public good, implying the strong possibility of free-rider actions. • Why does the market fail to provide the socially desirable level of climate protection? We demonstrated why the market fails to provide the socially desirable level of public good.- revision! • Global public ‘bads’ exist when no market has emerged to provide protection because everyone benefits from one person’s actions: non-excludability and non- rivalry in consumption. • Economics treat climate change as the classic example of global stock externality. • We distinguish between a stock and a flow pollutant. Stock pollutant is concentration- the accumulated carbon in the atmosphere like water ins a bathtub. Flow pollutant is the emission; the annual rate of emission like water flowing into a tub. • Climate change is the effect from the global carbon stock. The concentration of the green house gases give rise to climate change. • This makes dealing with climate change very tricky because changes in any one year’s emission have trivial effect on the current overall concentrations and for that matter, the effect on climate change. • The public good nature of climate change implies that it is the sum of all the carbon emitted around the globe that matters; all climate protection is non-rival and non- excludable. This is crucial for any solution to dealing with climate change. Today the industrialized world contribute the largest portion of emissions but soon developing countries like China and India would be the largest emitters. International cooperation is the key to effective abatement. Analyzing the Cost and Benefits of Climate Change. • We define the cost of climate change as what society has to forgo to pursue climate policy. • Benefit refers to the gains from reducing climate change risks by lowering emissions or enhancing the capacity for adaptation. The benefits of climate protection can be categorized into four four broad sets: • 1. Avoided losses to market goods and services such as the effect of drought on farming outputs, less potable water etc • 2. Avoided losses on non-market goods such as coastal areas, less biodiversity etc • 3. Catastrophes such as hurricanes, frequent outbreaks of infectious diseases such as cholera, malaria, zika etc. • 4. Effects from less use of fossil fuels such as less air pollution. • Estimate of the impact of climate change on the world GDP ranges between 1% and 2 % Costs and Benefits of Climate Protec>on • Estimates of climate protection costs range from modest of -0.5% to -3% loss of global GDP . The Clinton Administration estimated that it will cost the US about less than 0.5% ($10 billion) drop in annual GDP to meet emission targets; 5% rise in gasoline prices, lower electricity rates, no major impact of employment rate. • Other studies suggests that US GDP can take an annual hit of nearly 3%, trade deficit would increase by billions, gasoline price would increase by 50% and electricity prices would nearly double 2 million US jobs would disappear. The global cost have been estimated at over $700 billion; US bearing about two-thirds of it. Creang Economic Incen>ves to Deal with Climate Change • Economic incentives can deal with climate change problem by creating a market price for carbon which is otherwise treated as a free good. This price would create a tangible financial reason to reduce carbon emissions and provides the means to do so at low cost. • Taxes and Tradable permits trading are two such tools. People respond to these new prices by switching to less-carbon intensive alternatives, increase energy efficiency per unit of output by using less energy intensive technologies, adoption technologies to reduce emissions, reducing the production of high-cost, carbon intensive goods, increasing sequestration of carbon; developing and refining new technologies. • Carbon taxes work by taxing fossil fuels. Taxing fossil fuels work because their carbon content is easily ascertained. • Emission trading allows regulated emitters to buy emission reduction efforts from other emitters; in effect, contracting other emitters whose abatement costs are less than their own to make reductions for them. Internaonal Cooperaon on Climate Change • The free rider incentive of climate protection cause emissions to be abnormally high, but they also inhibit investment in research and development, a key ingredient in promoting innovative, low-carbon technologies.