Humans have caused global warming for 180 years

By AG Staff Writer 24 August 2016
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The global warming we are experiencing today started almost two centuries ago – much earlier than scientists expected.

HUMAN ACTIVITY HAS been causing global warming since the early stages of the Industrial Revolution, according to new research published today.

The research project involved 25 scientists from across Australia, the USA, Europe and Asia, and is published in the journal Nature.

The scientists looked at natural records of climate variations across the world’s oceans and continents over the past 500 years, including climate histories preserved in corals, tree rings and ice cores. They found that human-induced warming is not just a 20th-century phenomenon, but is first detectable in the Arctic and tropical oceans around the 1830s – much earlier than scientists had expected.

Lead researcher Associate Professor Nerilie Abram from ANU explains the findings. (Source: courtesy ANU)

“It was an extraordinary finding,” said Associate Professor Nerilie Abram from the Australian National University (ANU) Research School of Earth Sciences and ARC Centre of Excellence for Climate System Science.

“It was one of those moments where science really surprised us. But the results were clear. The climate warming we are witnessing today started about 180 years ago,” said Nerilie, who is lead author of the paper.

The scientists also analysed climate model simulations over thousands of years, including experiments used for the latest report by the United Nations Intergovernmental Panel on Climate Change (UN IPCC). They found that simulations in which only greenhouse gases were changed produced the same mid-19th century onset of warming as what they found in the natural records.

The findings suggest the Earth’s climate responded rapidly to even the relatively small increases in atmospheric greenhouse gas levels during the early stages of the Industrial Revolution.

The researchers also studied major volcanic eruptions in the early 1800s and found they were only a minor factor in the early onset of global warming.

The scientists involved in the research were working together as part of the International Past Global Changes 2000 year (PAGES 2K) Consortium.