Emissions of Greenhouse Gases worldwide.
By :Shoaib Habib Memon
The Sun powers Earth’s climate, radiating energy at very short
wavelengths, predominately in the visible or near-visible (e.g., ul-
traviolet) part of the spectrum. Roughly one-third of the solar
energy that reaches the top of Earth’s atmosphere is reflected di-
rectly back to space. The remaining two-thirds is absorbed by the
surface and, to a lesser extent, by the atmosphere. To balance the
absorbed incoming energy, the Earth must, on average, radiate the
same amount of energy back to space. Because the Earth is much
colder than the Sun, it radiates at much longer wavelengths, pri-
marily in the infrared part of the spectrum. Much
of this thermal radiation emitted by the land and ocean is ab-
sorbed by the atmosphere, including clouds, and reradiated back
to Earth. This is called the greenhouse effect.
Increasing emissions of greenhouse gases due to human activities worldwide have led to a substantial
increase in atmospheric concentrations of long-lived and other greenhouse gases. Every country around the world emits greenhouse
gases into the atmosphere, meaning the root cause of climate change is truly global in scope. Some
countries produce far more greenhouse gases than others, and several factors—such as economic
activity (including the composition and efficiency of the economy), population, income level, land use,
and climatic conditions—can influence a country’s emissions levels.
Like the U.S. Greenhouse Gas Emissions indicator, this indicator focuses on emissions of gases covered
under the United Nations Framework Convention on Climate Change: carbon dioxide, methane, nitrous
oxide, and several fluorinated gases. These are all important greenhouse gases that are influenced by
human activities, and the Convention requires participating countries to develop and periodically submit
an inventory of these emissions.
Data and analysis for this indicator come from the World Resources Institute’s Climate Analysis
Indicators Tool (CAIT), which compiles data from peer-reviewed and internationally recognized
greenhouse gas inventories developed by EPA and other government agencies worldwide. Global
estimates for carbon dioxide are published annually, but estimates for other gases, such as methane and
nitrous oxide, are available only every fifth year.
Each greenhouse gas has a different lifetime (how long it stays in the atmosphere) and a different ability
to trap heat in our atmosphere. To allow different gases to be compared and added together, emissions
are converted into carbon dioxide equivalents. This step uses each gas’s 100-year global warming
potential, which measures how much a given amount of the gas is estimated to contribute to global
warming over a period of 100 years after being emitted.
“Climate change is an important problem that needs strong action, and”Many times, long-term global problems such as climate change are hard to act on, but here we show that reducing greenhouse gas emissions can have near-term, local benefits for health, as well, which might strengthen the arguments for action with governments and citizens.”