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To Keep the Warming Limited with Dr. Veerabhadran Ramanathan – California China Climate Institute

By Megan Bergeron

What do these Climate Science terms mean?

Examples of fossil fuel emissions are coal or gas. Methane emissions are emitted by human activities such as leakage from natural gas systems and the raising of livestock, as well as by natural sources such as wetlands. They can be around for up to 12 years. Refrigerants are best described as chlorofluorocarbons (CFCs) that damage the ozone layer as extremely potent greenhouse gases. One kilogram of the refrigerant R410a has the same greenhouse impact as two tonnes of carbon dioxide, which is the equivalent of running your car for six months. Hydrofluorocarbons (HFCs) are man-made organic compounds that contain fluorine and hydrogen atoms, and are the most common type of organofluorine compounds. Most are gases at room temperature and pressure. Soot is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed fuel particles such as coal, cenospheres, charred wood, and petroleum coke that may become airborne during pyrolysis and that are more properly identified as cokes or char. Soot causes various types of cancer and lung disease.

What causes global warming?

Looking at Earth’s Climate History, climate is variable, with seasonal fluxes and millennial cycles, even long-term changes that occur over the course of millions of years. Over the course of the last 500 million years, the Earth has experienced both Ice House and Hot House periodes, each of which have altered the planet. An Ice House period is a geological period when Earth’s temperatures are cooler, and support glaciation. A Hot House period is a geological period when Earth’s temperatures are warmer, and are less suitable for glaciation. Today, Earth is in an Ice House period. However, due to anthropogenic climate change, Earth’s temperatures are warming at a rapid clip, glaciers are melting, and the planet is being altered because of it.

Climate change is caused by a disturbance in the balance of incoming and outgoing radiation, or heat trapped in the atmosphere. There are three important types of radiation at play here: Incoming solar radiation is the energy from the sun, and it enters the atmosphere in the form of shortwave radiation. Reflected solar radiation is the fraction of the energy from the sun that is reflected back into space by clouds, gasses in the atmosphere, or Earth’s surface. Outgoing longwave radiation is the energy that is emitted from Earth and its atmosphere. This is also known as thermal radiation. There is a natural balance of these three forms of radiation that keep Earth’s systems stable, and without human interference, fluctuate over long periods of time. The atmosphere plays a crucial role in maintaining Earth’s climate, and atmospheric gasses both reflect solar energy and help trap enough heat to warm Earth’s surface and support life. This is known as the greenhouse effect. Humans have changed this radiation balance.

Super pollutants, for example, are methane, hydrofluorocarbons (otherwise known as F-gases), black carbon, and ground-level ozone that are essential to curb alongside carbon dioxide. Humans have altered each of the radiations mentioned above. An example of a main super pollutant that works to alter the radiation system is CO2. According to the Center for American Progress, “While these pollutants account for far less of the total amount of annual greenhouse gas emissions than CO2, they nonetheless cause 40 percent of warming, or ‘radiative forcing.’ Radiative forcing, known as the “greenhouse effect,” occurs when solar radiation that passes through cloud cover reflects off of the Earth’s surface and is absorbed by clouds and greenhouse gases, or GHGs, in the atmosphere. Increased levels of GHGs reradiate upward and downward, warming the surface of the Earth.” Soot also contributes heavily to climate change.

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