Study confirms humans caused climate change
Scientists say industrial age triggered global warming over last century
Humans have been causing global warming for 180 years, according to an international study involving 25 scientists from around the world and Calvert County. The study, titled “The PAGES (Past Global Changes) 2K project,” dispels the myth that climate change is just a 20th-century phenomenon and addresses the debate of whether man or nature caused climate change.
“Enough people in the United States are questioning whether humans caused global warming — this is a nice piece of evidence that we are,” said University of Maryland Center for Environmental Science Chesapeake Biological Laboratory
Research Assistant Professor Hali Kilbourne, who studies paleoclimate, or climate from a former period, comparing records to understand how the climate is changing today and what could happen in the future. Kilbourne lent her expertise to the study dating back to 2011.
Prior to the 1900s, direct measurements of climate were rare. To come to the conclusion that humans were responsible for the degradation of the climate, the team studied climate reconstructions dating back 500 years to identify when the current warming trend began. Much to their surprise, they found the earliest signs of greenhouse warming dated back to the Industrial Revolution. It originated in the Arctic and tropical oceans around the 1830s. Europe, Asia and North America trailed, thereafter.
“We are already looking at a perturbed system — we have to recognize that. Now we know there is another 70 years of warming before the 1900s,” Kilbourne said, adding that the study confirmed humans caused the modern warming trend.
“During the Industrial Revolution, we as human beings started to burn fossil fuels. A classic example is the invention of the steam engine that ran on trains, steam boats and the modern industrial factory. Before that, people made stuff in their homes,” explained Kilbourne.
Fossil fuels are natural fuels such as coal or gas that are derived from the remains of past living plants and animals. When they are burned, carbon dioxide and other gases are released into the atmosphere and retained, causing the planet to warm. It is also referred to as the greenhouse effect.
Kilbourne, who has been at the Chesapeake Biological Lab in Solomons since 2009, is tasked with giving historical context to the changeability of modern climate for the purpose of educating others on the processes causing variations in climate both seasonally and over an extended period of time.
The methodology used for this project included studying natural records of temperatures across all seven continents and five oceans of the world. Temperature histories are preserved in corals, sediment layers, stalactites in caves, tree rings and ice cores. Like a thermometer, coral skeletons can record the temperature of the on past environmental changes and promoting the synthesis of scientific knowledge and data.
“The goal is to understand the climate system. These data can help us to understand regional implications,” explained Kilbourne, referring to the synthesis of work on the climate of continents and the climate of oceans. By understanding the earth’s past environment, scientists can better predict future climate and environment, and develop strategies for greater sustainability.