Global warming may have been started thousands of years ago by early humans. A new study blames the world’s first farmers for setting the effects of climate change in motion.
An analysis of ice-core climate data, ancient pollen samples, and other archaeological evidence is suggesting slash-and-burn farming by our earliest ancestors 7,000 years ago slowed the planet’s natural cooling process. A climate change effect that may be warming the planet even today.
In a theory named “early anthropogenic hypothesis,” a team of researchers claim that carbon dioxide levels began rising about 7,000 years ago, while methane rose about 5,000 years ago. The study was led by William Ruddiman, a climate scientist with the University of Virginia.
The report, published in a recent edition of the journal Reviews of Geophysics, contends that data collected over the past few years, specifically from 800,000-year-old ice-core samples, indicate an expected cooling period was stopped once humans began large-scale farming. The researchers believe the Earth should have entered a natural ice age, which never occurred.
Ruddiman says the scientific evidence places some responsibility on human actions for the effects of global warming.
“Early farming helped keep the planet warm. After 12 years of debate about whether the climate of the last several thousand years has been entirely natural or in considerable part the result of early agriculture, converging evidence from several scientific disciplines points to a major anthropogenic influence.”
However, some are skeptical of the study since far fewer people inhabited the planet back then and the more recent Industrial Age accounts for much of the excess greenhouse gas lingering in the atmosphere.
Several years ago, Ruddiman introduced a different controversial theory that blamed humans for causing global climate change. In a previous paper, he claimed the burning of large forests to make way for crops and livestock may have spewed substantial amounts of carbon dioxide and other gases into the air. This premise is still being debated today by climate change experts.
Was global warming responsible for 2015 being the hottest year on record?
According to the U.S. National Oceanic and Atmospheric Administration and NASA, 2015 was Earth’s warmest year since record-keeping began in 1880. Previously, 2014 held the title.
The planet’s average temperature was 1.62 degrees Fahrenheit hotter in 2015 than any other year in the last century. For 10 of the last 12 months, global temperatures tied or broke the existing monthly record. In the U.S., December was not only the warmest on record, but also the wettest.
Weather scientists believe much of the increased warmth was created by a major El Niño and not global warming. An El Niño is categorized by a significant warming trend of ocean waters in the central and eastern Pacific. The excess heat is also pushed into the atmosphere which can increase temperatures worldwide.
Last year’s El Niño was nearly as strong as the one occurring in 1998, which was also a record-setting warm year.
However, NASA did place some fault on climate change. “The planet’s average surface temperature has risen about 1.8 degrees Fahrenheit (1.0 degree Celsius) since the late-19th century, a change largely driven by increased carbon dioxide and other human-made emissions into the atmosphere,” a NASA press release stated.
Weather data indicate that 15 of the 16 hottest years on record have occurred since 2001 and the trend does not appear to be slowing. Many climate scientists are predicting 2016 will be even warmer.
Much of this surplus heat is being absorbed by the world’s oceans. As previously reported by the Inquisitr, another climate change study by the Laurence Livermore National Laboratory in California indicated that global warming is pushing up ocean temperatures at an alarming rate.
Due to variations in the orbit around the sun, the Earth cycles between warm interglacial periods and cooler glacial periods naturally. Beginning about 12,000 years ago, the planet entered a warm period known as the Holocene epoch.
While the planet seems to be getting hotter and hotter every year, scientists will continue to study the effects of global warming and debate whether the phenomenon is natural, man-made, or even exists at all.
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