of global climate change presents a complex combination of economic,
political, and scientific challenges.
Greenhouse-Gas Emissions
Greenhouse gases include carbon dioxide, methane, nitrous oxide, and
ozone. They are emitted through various industrial processes, especially
the burning of fossil fuels, the production of cement, and the use of
nitrogen-rich fertilizers in agriculture. As greenhouse gases (GHGs)
accumulate in the atmosphere, the rising atmospheric concentration
increases Earth’s average temperature and disrupts weather systems. It is
common to measure greenhouse gases in terms of their equivalent
amount of carbon dioxide, referred to as.
Flows Versus Stocks
The world’s total emissions of greenhouse gases is currently about 50
billion tonnes of per year, two-thirds of which are related to the
production or consumption of energy—residential and commercial
heating, transportation, electricity generation, and industrial processes.
These emissions are a flow that occur annually and have been on a
significant upward trend over the past century. Through the natural
respiration of forests and absorption by the oceans, Earth can absorb only
about 5 billion tonnes of GHGs every year. For each year that the total
flow of GHG emissions exceeds this natural absorptive level, the
atmospheric concentration of greenhouse gases increases. This
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