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|CLIMATE CHANGE IN CONTEXT
Ontario: Recent Trends in Greenhouse Gases
Introduction to Greenhouse Gases
Atmospheric gases that absorb and re-emit infrared (heat) energy are the greenhouse gases. Most common are carbon dioxide (CO2) and water vapour (H2O). Other greenhouse gases found in lesser amounts are methane (CH4), nitrogen oxides (NOx), and ozone (O3). (See Trends in Carbon Dioxide, Trends in Nitrous Oxide, Ozone Depletion, Ozone and Health.)
Greenhouse gases- carbon dioxide, nitrogen oxides and methane – make up less than 1 % of the atmosphere. In addition to water vapor, greenhouse gases keep Earth’s surface at 19oC.
The greenhouse effect gets its name because the greenhouse gases accumulate under the tropopause. This increase in greenhouse gas concentration changes in the heat energy balance. The temperature of the air between the Earth’s surface and the tropopause increases. The Earth then warms up as if it were in a greenhouse.
The diagram below shows all of the layers of the atmosphere far into space beyond earth.
1. What is the trend in a) pressure (mb) b) temperature (0 C) that accompany the increase in altitude above the earth?
2. Greenhouse gases from earth accumulate within the troposphere. Approximately how many kilometers above the surface of the earth is the tropopause or boundary?
3. Where is the ozone layer?
ACTIVITY 2 Research
1. At what altitude do the astronauts orbit above the Earth?
2. What do we call the parts of the biosphere on the Earth’s surface?
There are a number of entirely human-made greenhouse gases in the atmosphere, such as the halocarbons and other chlorine and bromine containing substances, dealt with under the Montreal Protocol. They are being considered by policymakers with more attention, since they are part of the greenhouse gas commitments of the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC).
There are some natural processes that produce greenhouse gases such as transpiration, and forest fires started by lighting. Most of the processes are a result of human activities and many of these began with the Industrial Revolution in the 1800’s.
Human emissions are currently adding @28 tonnes CO2 per year. Doubling concentration from 0.03% to 0.06% by end of the twenty-firsts century is predicted, with the possibility of tripling! Ratios of Carbon 12, 13and 14 are used to track this. See maps for Ontario Nitrate and Sulphate levels as these molecules are combinations such as sulphuric acid ( H2SO4) where the SO4is known as the sulphate part of the molecule.
Adding greenhouse gases to our atmosphere from human activities must be considered in context with the all of the layers of the atmosphere. Adding any gas increases its concentration beyond the natural concentration that is cycled and balanced by the natural Earth systems.
The following diagram shows the major sources of the greenhouse gases involved in commitments in the Kyoto
Carbon Dioxide, The Carbon Cycle, and Emissions
Increasing carbon dioxide (CO2) concentrations cause major disturbances of carbon dynamics in the biosphere – home to natural ecosystems. Carbon dioxide is a greenhouse gas released in processes that break down carbon compounds such as combustion, or burning of fuels as well as processes of respiration and decay. CO2 is both stored and released as calcium carbonate in limestone and sea shells. CO2 is taken in and used as a raw material for photosynthesis by all green plants from marine and fresh water algae to trees.
Carbon is temporarily stored as carbon dioxide dissolved in the oceans or sequestered as carbohydrates in plant cell walls, starches, fibers, and wood. The carbon cycle is completed when carbon dioxide is released. For example, into the air when plants and animals breathe, decay or are burned. Humans overload the carbon cycle by burning more fuels, especially fossil fuels, producing more carbon dioxide than the terrestrial and aquatic ecosystems normally absorb or are able to recycle.
The small particles or particulate matter that are also released in emissions influence global temperatures by changing the albedo affect of the planet. Atmospheric studies after the eruptions of volcanoes help understand these long-term effects. See also Section 6.2.2c, Human Health.
Temperature changes should also be examined in the context of changes in CO2 concentrations.
See PRESENT Global CO2. See Ontario smog days. See Climate Forcings. See Section 6.2.1: Projections for Ontario Greenhouse Gases.
For Global Greenhouses gases CO2, see Section 5.1.1.a
For Other Global Greenhouse gases, see Section 5.1.1b Methane, Nitrogen Oxides
Ontario’s climate history must be read within the context of this figure. Note the full scope of the factors that cause warming of the earth as radiant energy from the sun.
Note also the international science community IPCC has high confidence only for the first set of factors.
1. What is the trend seen in emissions per year for Ontario?
2. Plot this data.
a) Examine the following chart and list the sectors represented in the data.
b) What sectors are missing?
Research: Find the complete data for Ontario on the web.
The graph below represents one page of the greenhouse gas emissions data for Ontario in one decade.
Source: Environmental Signals, Environment Canada, 2003
1. State the proper name of each of the gases listed on the y axis.
2. What is the percentage increase over this decade?
3. What are the most common sources of these gases? Hint: check the sectors.
ACTIVITY 5 Research
1. What percent reduction will Ontarians have to make to meet the Kyoto protocol?
2. How do you propose all citizens can meet this target?
3. What government policies would ensure that this target is met?