Quantcast

The Climate Crisis Is the First Truly Global Climate Shift in the Past 2,000 Years, Studies Confirm

Climate
Arturo de Frias photography/ Moment / Getty Images

The current climate crisis is unique in the last 2,000 years of history, a trio of papers has found, in that it is the only truly global climate shift during the last two millennia.


Previous anomalies like the Little Ice Age, when it was possible to skate on the Thames, were more regional in scope, while the warming trend at the end of the 20th century affected more than 98 percent of the planet, Reuters reported.

"The main takeaway is that climate variability in the contemporary period is very different than what's happened in the past 2,000 years," Columbia University climate scientist Nathan Steiger, who co-authored one of the papers published in Nature Wednesday, told Reuters. "This is definitely further evidence that fossil fuels and anthropogenic activity actually has fundamentally changed the climate," he added.

Some climate deniers have pointed to past climate shifts to argue that there is nothing new or human-caused about the current warming period. The Medieval Climate Anomaly warmed temperatures from 800 to 1200 AD and the Little Ice Age saw temperatures fall from the 1300s to the 1850s, but the new research shows that these and other events were much more localized than current climate change. None of them covered more than half the globe at any one time, according to The Guardian.

In the past, researchers had taken evidence for these warming and cooling periods in Europe and North America and assumed they applied to the rest of the globe, the University of Bern explained in a press release. But for this week's papers, researchers consulted the PAGES (Past Global Changes) database of worldwide climate data from tree rings, ice cores, lake sediments and corals.

"It's true that during the Little Ice Age it was generally colder across the whole world," research team leader Raphael Neukom of the Oeschger Center for Climate Change Research at the University of Bern said, "but not everywhere at the same time. The peak periods of pre-industrial warm and cold periods occurred at different times in different places."

For example, the Little Ice Age was coldest in the Pacific in the 15th century, Europe in the 17th century and elsewhere in the 19th century, The Guardian reported.

"This paper should finally stop climate change deniers claiming that the recent observed coherent global warming is part of a natural climate cycle. This paper shows the truly stark difference between regional and localised changes in climate of the past and the truly global effect of anthropogenic greenhouse emissions," University College London climatology professor Mark Maslin told The Guardian.

The Nature paper was accompanied by a second, published in Nature Geoscience, that focused on the impacts of five large volcanic eruptions during the early 19th century that caused cooler temperatures, drought in Africa and the advance of glaciers in the Alps, the University of Bern further explained.

Because these eruptions occurred at the start of the industrial revolution, researchers say it is difficult to determine how volcanism interacted with the increasing burning of greenhouse gasses to impact climate at that time.

"It does sort of mask the effect of industrial processes, where they are starting to omit more CO2, because they counteract each other," Steiger told Smithsonian.com. "So volcanoes could cool, and humans would warm by the release of greenhouse gasses. It's tricky to parse out what's what."

This matters because international targets like the Paris agreement seek to limit warming to certain amounts above a pre-industrial norm.

"Given the large climatic changes seen in the early 19th century, it is difficult to define a pre-industrial climate, a notion to which all our climate targets refer," lead author and University of Bern climatologist Stefan Brönnimann said in the university release.

But what is clear is that today's warming is unprecedented during the study period. A final paper, also published in Nature Geoscience, concluded that the rates of warming documented in the second half of the 20th century were the fastest in 2,000 years.

That finding "highlights the extraordinary character of current climate change," Neukom told Smithsonian.com.

EcoWatch Daily Newsletter

Pro-environment demonstrators on the streets of Washington, DC during the Jan. 20, 2017 Trump inauguration. Mobilus In Mobili / Flickr / CC BY-SA 2.0

By Dr. Brian R. Shmaefsky

One year after the Flint Water Crisis I was invited to participate in a water rights session at a conference hosted by the US Human Rights Network in Austin, Texas in 2015. The reason I was at the conference was to promote efforts by the American Association for the Advancement of Science (AAAS) to encourage scientists to shine a light on how science intersects with human rights, in the U.S. as well as in the context of international development. My plan was to sit at an information booth and share my stories about water quality projects I spearheaded in communities in Bangladesh, Colombia, and the Philippines. I did not expect to be thrown into conversations that made me reexamine how scientists use their knowledge as a public good.

Read More
Mt. Rainier and Reflection Lake on Sept. 10, 2015. Crystal Geyser planned to open a bottling plant near Mt. Rainier, emails show. louelke - on and off / Flickr

Bottled water manufacturers looking to capture cool, mountain water from Washington's Cascade Mountains may have to look elsewhere after the state senate passed a bill banning new water permits, as The Guardian reported.

Read More
Sponsored
Large storage tank of Ammonia at a fertilizer plant in Cubatão, Sao Paulo State, Brazil. Luis Veiga / The Image Bank / Getty Images

The shipping industry is coming to grips with its egregious carbon footprint, as it has an outsized contribution to greenhouse gas emissions and to the dumping of chemicals into open seas. Already, the global shipping industry contributes about 2 percent of global carbon emissions, about the same as Germany, as the BBC reported.

Read More
At high tide, people are forced off parts of the pathway surrounding DC's Tidal Basin. Andrew Bossi / Wikimedia

By Sarah Kennedy

The Jefferson Memorial in Washington, DC overlooks the Tidal Basin, a man-made body of water surrounded by cherry trees. Visitors can stroll along the water's edge, gazing up at the stately monument.

But at high tide, people are forced off parts of the path. Twice a day, the Tidal Basin floods and water spills onto the walkway.

Read More
Lioness displays teeth during light rainstorm in Kruger National Park, South Africa. johan63 / iStock / Getty Images

By Jessica Corbett

Ahead of government negotiations scheduled for next week on a global plan to address the biodiversity crisis, 23 former foreign ministers from various countries released a statement on Tuesday urging world leaders to act "boldly" to protect nature.

Read More