ESSE 2210 Quiz 3 PDF

Week 7 Climate Change: - Climate Change; - Introduction; - Climate change and ozone thinning are 2 different problems, - Thinning ozone layer allows more uv light to penetrate to the earth’s surface, potentially burning our skin - Past Climate Change - Earth’s c...

Week 7 Climate Change: - Climate Change; - Introduction; - Climate change and ozone thinning are 2 different problems, - Thinning ozone layer allows more uv light to penetrate to the earth’s surface, potentially burning our skin - Past Climate Change - Earth’s climate, determined mostly by its average temperature and average precipitation. - Climate change is neither new or unusual, shifted due to volcanic emissions, changes in solar energy input, continents moving as a result of shifting tectonic plates - Troposphere temp has changed over the past 100 years - We have good fortune living in an interglacial period, with a stable climate based on a moderate and steady global average. - During the past 1000 years, the average temperature of the atmosphere dropped slightly then began to rise again 200 years, coinciding with the industrial revolution. - Estimated changes in the troposphere CO2 levels correlate fairly closely with estimated variations in the average global temperature near the earth’s surface during the past 400 000 years. - The Earth’s Natural Greenhouse Effect - Certain gases in the atmosphere absorb heat and warm the lower atmosphere. - A natural process called the greenhouse effect warms the Earth’s lower atmosphere and surface - Clouds, water vapor, carbon dioxide, and other gasses absorb heart - These clouds and gases radiate heat as longer wavelengths in all directions. - A natural cooling process also takes place at the Earth's surface. Large quantities of heat are absorbed by the evaporation of liquid surface water, and the water vapor molecules rise, condense to form droplets in clouds, and release their stored heat higher in the troposphere - Natural heating and cooling, the Earth's average surface temperature is about 15°C - The Two Major Greenhouse Gases Are Water Vapour and Carbon Dioxide - The two greenhouse gases with the largest concentrations are water vapour, controlled by the hydrologic cycle, and carbon dioxide, controlled by the carbon cycle. We have added huge quantities of carbon dioxide to the troposphere. - Climate Change and Human Activities - Humans Have Increased Concentrations of Greenhouse Gases in the Troposphere by Burning Fossil Fuels, Clearing and Burning Forests and Grasslands, Raising Large Numbers of Livestock such as Cattle, Planting Rice, and Using Inorganic Fertilizers - Humans Have Increased Concentrations of Greenhouse Gases in the Troposphere by Burning Fossil Fuels, Clearing and Burning Forests and Grasslands, Raising Large Numbers of Livestock such as Cattle, Planting Rice, and Using Inorganic Fertilizers - One has been the sharp rise in the use of fossil fuels, which release large amounts of CO2, CH4 and NO2 into the troposphere. - A second process is deforestation and the clearing and burning of grasslands to raise crops and build cities, which release CO2 and N2O. - Third is the raising of an increasing number of cattle and other livestock that release methane as a result of their digestive processes. - A fourth process is cultivation of rice in paddies and use of inorganic fertilizers that release N2O into the troposphere. - First, the past three decades were each warmer than the previous one, and the 30 years from 1983 to 2012 were very likely (90%to 100% probability) the warmest 30- year period of the past 800 years in the northern hemisphere, and likely (66%to 100% probability) the warmest of the past 1400 years - Second, from 1880 to 2012 the average global temperature of the troposphere near the Earth's surface has risen 0.85°C - Virtually certain that the upper 700 meters of the oceans became warmer globally between 1971 and 2010, - Glaciers and floating sea ice in many parts of the world are melting - 1901 and 2010 the world's average sea level rose by 0.19 meters (7.5 inches) - Global Warming vs. Global Climate Change - Global warming and global climate change are often used interchangeably, but they are not the same - Global warming refers to temperature increases in the troposphere - Global climate change is a broader term that refers to changes in any aspect of the Earth's climate - Some of the World's Floating Ice and LandBased Glaciers Are Slowly Melting, Reflecting less Incoming Sunlight Back into Space, and Helping Warm the Troposphere Further - According to the World Wildlife Fund, the diminishing levels of sea ice force polar bears to swim up to 100 kilometres (62 miles) in search of sea ice from which to hunt seals. - Why should we care if there is less ice in the Arctic? The answer lies in the albedo - Positive Feedback Effect - A rise in the Earth's temperature can cause gradual melting of some of the Earth's ice caps - Many scientists believe that the biggest long-term climate danger comes from Greenland. - They are especially concerned about partial or eventually complete melting of the land-based glaciers or ice sheets that cover Greenland. - Another example of positive feedback is the melting of the Canadian Permafrost and the release of methane (CH4) trapped in the soil. - Projecting Future Changes in The Earth’s Temperature - What Is the Scientific Consensus about Future Changes in the Earth’s Temperature? Hotter Times Ahead? - Most Climate Scientists Agree that Human Activities Have Influenced Recent Temperature Increases and Will Lead to Further Significant Temperature Increases during This Century - Surface temperature is projected to rise over the 21st century under all assessed emission scenarios. By 2081-2100, the temperature increase is likely to be between 2.6°C and 4.8°C under the least optimistic scenario (which assumes higher greenhouse gas emissions) and between 0.3 °c and 1.7 °c under the RCP with the lowest emissions - The level of surface warming by the late 21st century will be determined mainly by the cumulative emissions of CO2, past and future, and by natural climate variability - “Many aspects of climate change and associated impacts will continue for centuries, even if anthropogenic emissions of greenhouse gases are stopped” - IPCC and other climate scientists holding the consensus view agree that current climate models need to be improved. - A few climate scientists disagree with the consensus view about future temperature changes in the Earth's atmosphere. They say we know too little about how the Earth's climate works to make reliable projections about such changes. - Why Should We Be Concerned About a Warmer Earth? The Speed of Change Is What Counts? - A Rapid Increase in the Temperature of the Troposphere Would Give Humans and Other Species Little Time to Deal with Its Effects - Climate scientists warn that the concern is not just a temperature change but how rapidly it occurs, regardless of cause - According to the IPCC, it is very likely that this will be the fastest temperature change of the past 1000 years - IPCC = The intergovernmental panel on climate change - These are major changes in the Earth's atmospheric conditions. An increase in the Earth's average temperature within a few decades or a century gives us little time to deal with its effects. - Scientists have identified a number of natural and human-influenced factors that might amplify (positive feedback) or dampen (negative feedback) projected changes in the average temperature of the troposphere - Factors Affecting the Earth’s Temperature - There Is Uncertainty about How Much CO2 and Heat the Oceans Can Remove from the Troposphere and How Long They Might Remain in the Oceans - The oceans help moderate the Earth's average surface temperature by removing about 29% of the excess CO2 we pump into the atmosphere as part of the global carbon cycle - They also absorb heat from the atmosphere and slowly transfer some of it to the deep ocean, where it is removed from the climate system for long, but unknown, periods of time. - Ocean Currents - mechanism - A warmer planet would be a rainier one, which, coupled with melting glaciers, would increase the amount of fresh water flowing into the North Atlantic. This could slow or even jam the currents by diluting the salt water and making it more buoyant (less dense) and less prone to sinking. - Scientists do not know how rapidly heat absorbed by the ocean from the troposphere can be transferred to the deep ocean by such currents and other mixing processes - Dissolved CO2 - Scientists do not know whether, over the next few decades,the oceans will release some of their stored heat and dissolved CO2 into the troposphere, thereby amplifying its global warming. - Evidence suggests that large changes in the speed of the ocean currents in this conveyor belt, and its stopping and starting, contributed to wild swings in northern hemisphere temperatures during past ice ages. - Scientists are trying to learn more about how these currents operate to evaluate the likelihood of the loop slowing down or stalling during this century and the effects this might have on regional and global atmospheric temperatures. - How Might Stored CO2 Affect Water Chemistry? Ocean Acidification - When Oceans Absorb CO2 They Become More Acidic, with Potential Consequences for Marine Life - Scientists are particularly concerned that corals would be negatively impacted since these animals have large requirements for calcium carbonate to build their exoskeletons, and since corals are already stressed by warming seas. - Paleoceanographic evidence has been discovered that shows there was a massive disappearance of carbonate 55 million years ago, as determined by examination of sediment cores - Scientists speculate that an abundant release of methane at the time contributed to global warming, and as the methane was oxidized to CO2, ocean acidification resulted in the disappearance of calcium carbonate from ocean sediment. - higher concentrations of atmospheric CO2 will lead to increased ocean acidification - schemes that involve disposal of CO2 into the ocean now seem inadvisable in view of our awareness of ocean acidification - How Might Outdoor Air Pollution Affect the Troposphere’s Temperature? A Temporary Effect - Aerosol Pollutants and Soot Produced by Human Activities Can Warm or Cool the Troposphere, but such Effects Will Decrease with Any Decline in such Outdoor Air Pollution - Can Increased CO2 Levels Stimulate Photosynthesis and Remove More CO2 from the Air? A Temporary and Limited Effect - Increased CO2 in the Troposphere Could Increase Plant Photosynthesis, but Several Factors Can Limit or Offset This Effect - Some studies suggest that more CO2 in the troposphere could increase the rate of plant photosynthesis in areas where there are no other limiting factors, such as lack of water or soil nutrients. This would remove more CO2 from the troposphere and help slow atmospheric warming. - How Might a Warmer Troposphere Affect Methane Emissions? Accelerated Warming - Warmer Air Can Release Methane Gas Stored in Bogs, Wetlands, and Tundra Soils, Causing a Feedback Loop that Makes the Air Warmer - Global warming could be accelerated by an increased release of methane (a potent greenhouse gas) from two major sources. One is bogs and wetlands, and the other is ice-like compounds called methane hydrates trapped beneath the Arctic permafrost. - Possible Effects of a Warmer World - Projected effects of a warmer atmosphere for the world. Current models of the Earth’s climate can not make reliable projections about where such effects might take place at a regional level and how long they might last. - - Sea levels may rise as much as 7 metres (23 feet) if most of the ice on Greenland and in the Canadian Arctic melts. This would cause flooding problems for coastal cities and for many islands - Freshwater coastal aquifers would be contaminated with salt water.According to the IPCC (2013), this becomes increasingly likely if warming of between 1 and 4 degrees is sustained beyond the end of this century - Adapting to Climate Change - There Is Disagreement over What We Should Do about the Threat of Global Warming - Nearly all climate scientists agree that the Earth's temperature is very likely to increase during this century and that human activities play a part in this change - there is debate among scientists over the causes of these changes (natural or human),how rapidly they might occur, the effects on humans and ecosystems, and how we should respond to this potentially serious long-term global threat - Economists and policymakers also disagree over how we should respond to the threat of climate change. - One is to do more research before acting. - scientists and economists call for more research and a be t ter understanding of the Earth's climate system - A second and rapidly growing group of scientists, economists, business leaders, and political leaders especially in the European Union believe that we should act now to reduce the risks from climate change brought about by global warming. - They argue that the potential for harmful economic, ecological, and social consequences is so great that action should not be delayed. - A third strategy is to act now as part of a no-regrets strategy - For example, we should be seizing the chance to advance alternative energy sources, for many reasons aside from global warming. - Reduced burning of fossil fuels, especially coal, will lead to sharp reductions in air pollution that lowers food and timber productivity, decreases biodiversity, and prematurely kills large numbers of people. - As well, we should be improving energy efficiency, which has numerous economic and environmental advantages.We should also be practising sustainable forestry for economic, biodiversity, and health reasons - aside from global warming issues - What Can We Do to adapt? Conserve Energy, Use Renewable Energy, and Intercept Greenhouse Gas Emissions? ONLY? - We Can Improve Energy Efficiency, Rely More on Carbon-Free Renewable Energy Resources, and Find Ways to Keep Much of the CO2 We Produce out of the Troposphere - improve energy efficiency to reduce fossil fuel use - shift from carbon-based fossil fuels to a mix of carbon-free renewable energy resources - sequester or store as much as possible in soil, in vegetation,underground, and in the deep ocean - Scientists are also developing new power plant designs (nuclear energy? that would eliminate smokestack emissions of CO2 and other pollutants. - One approach is to develop modified forms of coal gasification to increase the energy efficiency of coal-fired power plants from 35% to 70% - However, if such plants can be developed,they are likely to be quite costly and it would take many decades for them to replace existing power plants - Can We Remove and Store (Sequester) Enough CO2 to Slow Global Warming?Are Output Approaches the Answer? - We Can Prevent Some of the CO2 We Produce from Circulating in the Troposphere, but the Costs May Be High, and the Effectiveness of Various Approaches Is Unknown - One possible way to remove CO2 from the atmosphere is to plant trees that store (sequester) it in biomass. - A second approach is soil sequestration in which plants such as switchgrass are used to remove CO2 from the air and store it in the soil. - A third strategy to reduce the release of carbon dioxide and nitrous oxide from soil. - There are several problems with this strategy. One is that current methods that can remove about 90%of the CO2 from smokestack emissions consume a great deal of the energy produced by the power plant, reducing the net energy yield of so-called clean coal. - Governments Can Tax Greenhouse Gas Emissions and Energy Use, Increase Subsidies and Tax Breaks for Saving Energy and Using Renewable Energy, and Decrease Subsidies and Tax Breaks for Fossil Fuels. - How Can We Use the Marketplace to Reduce or Prevent Greenhouse Gas Emissions? Emissions Trading - Establishing a Global Emissions Trading Program Could Help Reduce Greenhouse Gas Emissions - It Will Very Likely Cost Us Less to Help Slow and Adapt to Global Warming now than to Deal with Its Harmful Effects Later?? - First, they do not include the huge cost savings from implementing many of the strategies, such as improving energy efficiency. - Second,they underestimate the ability of the marketplace to act rapidly when money is to be made from reducing greenhouse gas emissions. - What Is Being Done to Reduce Greenhouse Gas Emissions? - What Was the Kyoto Protocol? A Controversial International Agreement - In December 1997, more than 2200 delegates from 161 nations met in Kyoto, Japan,to negotiate a treaty to help slow global warming. - The resulting Kyoto Protocol required 39 developed countries to cut emissions of CO2, CH4 and NO2 to an average of about 5.2% below 1990 levels by 2012 - The Kyoto Protocol, the world's first binding agreement that set targets to reduce greenhouse gas emissions, has been praised by many climate analysts as a small but important step in attempting to slow global warming - Opponents of the agreement claimed that it would be expensive to implement, result in loss of jobs, and make participating countries less able to compete economically. - What Is Being Done to Reduce Greenhouse Gas Emissions? - What Is the Paris Agreement? - Nearly 200 countries, rich and poor, will together aim to keep global temperature increase to well below 2°C. They will publicly report on their progress every five years - In December 2015, 196 nations concluded a new climate accord: the Paris Agreement. The successor to the Kyoto Protocol, the Paris Agreement establishes the goal of limiting temperature increases to “well below” 2°C above pre-industrial levels, while also striving for a more ambitious 1.5°C limit. - Critics have pointed out that, under the emission reduction plans submitted by participating nations prior to the Paris conference,the 2°C target will be missed by possibly as much as one degree