When Did Global Warming Start?

You may have asked yourself, "When did global warming start?" Global warming involves the raising of the earth's temperature through an interaction between sunlight and gasses in the atmosphere. You'd be surprised how long it's been going on.

When Did Global Warming Start To Be A Problem?
Global warming occurs when gasses such as methane, water vapor and carbon dioxide enter the atmosphere and create a layer that traps heat radiated by the earth itself. These gases (sometimes called greenhouse gasses) can come from natural or manmade sources. Here is a closer look at the issues and timing involved:

• Natural sources. Natural sources of greenhouse gas emissions include volcanic out-gassing, oceanic evaporation and animal biological processes. These sources tend to remain constant, although major volcanic events are evident in the geological record.
• Manmade sources. Manmade sources of green house gasses include industrial and agricultural processes. Industrially, the burning of fossil fuels is the greatest contributor of greenhouse emissions. On the agricultural side, clearing of forests increases the carbon output of soil and the raising of livestock produces and abundance of methane.
• The rhythm method. The global climate fluctuates over time, with periods of excess cold (called glacial periods) followed by periods of excess heat (called interglacial periods). This pattern of heat and cold extends back at least 800,000 years according to ice core records. Given this natural rhythm, it is fair to say that global warming has been around long before man came on the scene.
• Once more, with feeling. In the current interglacial period, carbon dioxide levels continue to rise instead of dropping as they have during other interglacial periods. Some scientists attribute this to agriculture activity (begun roughly 8,000 years ago) and industrial activity (begun less than 200 years ago). Over the past several decades, these scientists have made the case that human activity has greatly accelerated the rate of global warming beyond the naturally recorded rates.