New research matches ice core data with observational records
By Summit Voice
FRISCO — Mapping and analysis of ice core samples from the Arctic has helped Canadian and American scientists conclude that variations in Arctic surface temperatures from 1930 to the present can be linked to both anthropogenic and natural factor, including increased levels of greenhouse gases and sulphate aerosols from industrial activity and volcanic emissions.
The study, published this week in Scientific Reports, set out in part to better identify the drivers of Arctic warming and to explain why the temperature increases haven’t been uniform. The research involved a close look at historical aerosol records contained in ice cores by scientists working at the Desert Research Institute in Reno, Nevada.
“Unlike greenhouse gases, aerosols are short-lived in the atmosphere.” said Joe McConnell, a research professor at the Desert Research Institute who oversees DRI’s unique ultra-trace ice core analytical laboratory. “In order to understand their role in global climate you have to employ an array of sample sites and measurements. The records used in this study are part of a much larger array of historical aerosol records we are developing from ice cores collected from throughout the polar regions.”
McConnell adds that this new study, resulting from collaboration between Canadian and American environmental researchers utilizing state-of-the-art climate models and ice core analytical techniques, demonstrates the importance of aerosols in climate forcing.
The authors attribute warming from 1900-1939 to rapidly rising black carbon emissions, diminishing influence of the Santa Maria volcanic eruption in 1902, and warming North Atlantic sea surface temperatures. Cooling from 1939 to 1970 is attributed to cooling from anthropogenic sulfate aerosol emissions the Agung volcanic eruption in 1963, and falling North Atlantic surface temperatures.
More recently, the authors attribute warming from 1970 to present to increased anthropogenic greenhouse gas emissions, with a smaller contribution from warming North Atlantic sea surface temperatures.
Understanding the causes of Arctic climate change during this period is critical, said McConnell, because of the associated environmental and economic impacts.