The world is the warmest is has ever been in 4,000 years.
According to new research from Oregon State University, we’re living in a world that hasn’t been this warm in 4,000 years, a span of time formerly thought to be closer to 1,500 years.
The study, published Friday in the journal Science, also predicts that later this century, temperatures could rise to a record high for the modern geological era, the Holocene. This era began 12,000 years ago, and its mild climate is thought to have greatly aided human development as a species. The era’s rising temperature melted the vast expanses of ice that covered the Northern Hemisphere, allowing for the rise of agriculture and human civilization.
The research, led by Shaun Marcott, an earth scientist at Oregon State, collected climate data from the past 11,300 years, reconstructing almost the entire Holocene era. The team looked at the distribution of temperature-sensitive ocean organisms and other indicators to determine the past temperature data.
Why has the Earth been getting warmer for the past 12,000 years? The study agrees with past (less far-reaching) research that suggests early on in the Holocene, increased sunlight caused by wobbles in the Earth’s orbit caused rising temperatures that plateaued about 10,000 years ago. After keeping stable for 5,000 years after that, changing sunlight distribution caused the Earth to begin to cool. This cooling was interrupted briefly in the Middle Ages, during the Medieval Warm Period.
“We were on this downward slope, presumably going back toward another ice age,” Marcott told the New York Times. Scientists believe that, had it not been for human intervention, the Northern Hemisphere would have frozen over again. But because of the industrial development that has occurred in the past centuries, and the massive amounts of greenhouse gases created by the industrial revolution, we are not headed for another ice age.
Instead, modern temperatures are analogous to those 5,000 years ago, and by the end of the 21st century, temperatures will likely surpass those of the early Holocene.
