Quantcast

Groundbreaking Study Reaffirms Human Impact on Climate

Climate

TckTckTck

A groundbreaking new study, published in Nature Geoscience, has found that global temperatures were warmer between 1970 and 2000 than any other 30-year period in the last 1,400 years.

The research, compiled by 73 scientists from 28 institutions worldwide, is the most comprehensive reconstruction of global temperatures to date. It used corals, ice cores, tree rings, lake and marine sediments, historical records, cave deposits and climate archives to help establish temperature trends over the last 2,000 years.

Students use acoustic imaging to select a coring site at a lake in southern Alaska. Photo credit: Darrell S. Kaufmann, Northern Arizona University

The researchers aimed to chart change not just of the globe itself, but also of climate change in seven continental regions, studying more than 500 different sets of temperature records from all continents except Africa, where the evidence is still incomplete.

And while results could vary widely across continents, the research did confirm that a long period of cooling, between 1580 and 1880, was halted by a sharp reversal in the late nineteenth century. It also confirmed that the 30-year period between 1970 and 2000 was the warmest on land in at least 1,400 years.

While the research found that natural variability, such as volcanic eruptions and changes in solar irradiance can, and has, imprinted on the global climate systems to cause cooling historically, it once again affirms that these natural causes of climate variability do not and cannot explain the most recent period of global warming.

Examination of lake sediment core from southern Alaska shows intricate layering indicating environmental and climatic changes over centuries. Photo credit: Darrell S. Kaufman, Northern Arizona University

The timing of the warming period correlates directly with an increase in carbon emissions from human activity over the same period and broadly confirms an ever-growing message from climate scientists: climate change is happening, it is caused by humans and billions of people will fall victim to it without urgent action.

For example, the latest briefing from the World Meteorological Organisation (WMO) warns that scientific consensus that global climate is due to human activity is strong and should not be ignored, and the upcoming Intergovernmental Panel on Climate Change fifth report is expected to further bolster this overwhelming consensus.

The WMO reported that global average temperatures have risen an estimated 0.6°C (1.1°F) over the course of the 20th century, and continue to climb. They found 2001-2010 to be the warmest decade since satellite records began, 2010 the warmest year, and no year since 1985 having recorded a below average mean temperature.

The latest study is an important contribution to this growing body of research. It looked in detail at the differences in temperature change between individual continents and also provided temperature information for each year–creating a more detailed reconstruction than previous studies over the same time period.

Researchers used data from tree rings, ice cores and other sources to provide detailed records of last 2000 years. Creative Commons: Sheila Miguez, 2007

Lead author Professor Darrell Kaufman, Northern Arizona University in Flagstaff said:

Previous attempts to reconstruct temperature changes focused on hemispheric or global scale averages, which are important, but overlook the pronounced regional-scale differences that occur along with global changes. A key aspect of the consortium effort was to engage regional experts who are intimately familiar with the evidence for past climate changes within their regions.

Looking in this detail at how the Earth’s past temperatures have changed, the researchers say they are more able to separate the effects of human activity from fluctuations that occur naturally–something they say is vital to being able to track future projections on climate change.

Visit EcoWatch’s CLIMATE CHANGE page for more related news on this topic.

——–

Click here to tell Congress to Expedite Renewable Energy.

 

EcoWatch Daily Newsletter

Scanning electron micrograph of Yersinia pestis, which causes bubonic plague, on proventricular spines of a Xenopsylla cheopis flea. NIAID / Flickr / CC BY 2.0

A middle-aged married couple in China was diagnosed with pneumonic plague, a highly infectious disease similar to bubonic plague, which ravaged Europe in the middle ages, as CNN reported.

Read More Show Less
Milk made from almonds, oats and coconut are among the healthiest alternatives to cow's milk. triocean / iStock / Getty Images Plus

Dairy aisles have exploded with milk and milk alternative options over the past few years, and choosing the healthiest milk isn't just about the fat content.

Whether you're looking beyond cow's milk for health reasons or dietary preferences or simply want to experiment with different options, you may wonder which type of milk is healthiest for you.

Read More Show Less
Sponsored
Greta Thunberg stands aboard the catamaran La Vagabonde as she sets sail to Europe in Hampton, Virginia, on Nov. 13. NICHOLAS KAMM / AFP via Getty Images

Greta Thunberg, the teenage climate activist whose weekly school strikes have spurred global demonstrations, has cut short her tour of the Americas and set sail for Europe to attend COP25 in Madrid next month, as The New York Times reported.

Read More Show Less
The Lake Delhi Dam in Iowa failed in 2010. VCU Capital News Service / Josh deBerge / FEMA

At least 1,688 dams across the U.S. are in such a hazardous condition that, if they fail, could force life-threatening floods on nearby homes, businesses, infrastructure or entire communities, according to an in-depth analysis of public records conducted by the the Associated Press.

Read More Show Less

By Sabrina Kessler

Far-reaching allegations about how a climate-sinning American multinational could shamelessly lie to the public about its wrongdoing mobilized a small group of New York students on a cold November morning. They stood in front of New York's Supreme Court last week to follow the unprecedented lawsuit against ExxonMobil.

Read More Show Less
Sponsored

By Alex Robinson

Leah Garcés used to hate poultry farmers.

The animal rights activist, who opposes factory farming, had an adversarial relationship with chicken farmers until around five years ago, when she sat down to listen to one. She met a poultry farmer called Craig Watts in rural North Carolina and learned that the problems stemming from factory farming extended beyond animal cruelty.

Read More Show Less
People navigate snow-covered sidewalks in the Humboldt Park neighborhood on Nov. 11 in Chicago. Scott Olson / Getty Images

Temperatures plunged rapidly across the U.S. this week and around 70 percent of the population is expected to experience temperatures around freezing Wednesday.

Read More Show Less
A general view of the flooded St. Mark's Square after an exceptional overnight "Alta Acqua" high tide water level, on Nov. 13 in Venice. MARCO BERTORELLO / AFP / Getty Images

Two people have died as Venice has been inundated by the worst flooding it has seen in more than 50 years, The Guardian reported Wednesday.

Read More Show Less