August 24, 2016 Australian National University
An international research project has found human activity has been causing global warming for almost two centuries, proving human-induced climate change is not just a 20th century phenomenon….”…The climate warming we are witnessing today started about 180 years ago.” The new findings have important implications for assessing the extent that humans have caused the climate to move away from its pre-industrial state, and will help scientists understand the future impact of greenhouse gas emissions on the climate.
…The research, published in Nature, involved 25 scientists from across Australia, the United States, Europe and Asia, working together as part of the international Past Global Changes 2000 year (PAGES 2K) Consortium. Associate Professor Abram said anthropogenic climate change was generally talked about as a 20th century phenomenon because direct measurements of climate are rare before the 1900s.
…The data and simulations pinpointed the early onset of warming to around the 1830s, and found the early warming was attributed to rising greenhouse gas levels….humans only caused small increases in the level of greenhouse gases in the atmosphere during the 1800s. “But the early onset of warming detected in this study indicates the Earth’s climate did respond in a rapid and measureable way to even the small increase in carbon emissions during the start of the Industrial Age,” Dr McGregor said.
The researchers also studied major volcanic eruptions in the early 1800s and found they were only a minor factor in the early onset of climate warming.
Associate Professor Abram said the earliest signs of greenhouse-induced warming developed during the 1830s in the Arctic and in tropical oceans, followed soon after by Europe, Asia and North America. However, climate warming appears to have been delayed in the Antarctic, possibly due to the way ocean circulation is pushing warming waters to the North and away from the frozen continent.
Abram et al. Early onset of industrial-era warming across the oceans and continents. Nature, 2016; 536 (7617): 411 DOI: 10.1038/nature19082