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Observed coupling between surface temperature and atmospheric CO2 extended to 1.5 million years ago

Posted on December 1, 2019December 1, 2019 by Geoff Zeiss

Evidence from Antarctic ice cores have revealed a close correlation between surface temperature and atmospheric carbon dioxide concentration for the past 800,000 years (excluding the immediate present.) A recent analysis of Antarctic blue ice has found that the close correlation between temperature CO2 extends to 1.5 million years ago during the time when the glacial/interglacial period was 40,000 years.

Geospatial analysis reveals 20% of northern permafrost region susceptible to abrupt permafrost thawing

Posted on August 24, 2019 by Geoff Zeiss

Northern permafrost soils represent the largest terrestrial organic carbon pool on Earth. A study the northern circumpolar permafrost zones reveals that landscapes susceptible to abrupt thawing with the release of significant quantities of carbon dioxide and methane cover 20% of the northern permafrost region and store up to half its soil organic carbon.

Link between Milankovitch’s theory of orbital forcing and ice ages remains an open question

Posted on June 24, 2019August 13, 2019 by Geoff Zeiss

A seminal book by Milankovitch in 1941 proposed that the sequence of ice ages that has characterized long term changes in the Earth’s climate over the past hundreds of thousands of years was due to changes in the amount of solar radiation reaching the Earth as a result of small variations in the Earth’s orientation and orbit with respect to the sun. Since then research has shown that Milankovitch cycles by themselves do not determine the timing of glacial and interglacial cycles and that we still lack a unified mechanism that links changes in Earth’s orbit to ice ages.

Latest NASA research reveals several East Antarctica glaciers losing ice

Posted on December 12, 2018August 10, 2019 by Geoff Zeiss

In contrast to West Antarctica where several large glaciers have been losing ice for decades, East Antarctica glaciers have exhibited little evidence of ice loss but NASA’s latest detailed maps of East Antarctica ice velocity and elevation show that a number of glaciers have begun to lose ice over the past decade.

Emissions from electric power generation decoupled from economic growth in US

Posted on November 7, 2018August 10, 2019 by Geoff Zeiss

Between 2005 and 2017 the U.S. economy as measured by real GDP expanded by about 20 %. Over this same period, emissions from power generation dropped which is evidence of a decoupling between economic growth and power generation.

Increased methane in atmosphere sourced to fossil fuels and livestock

Posted on July 25, 2018August 17, 2019 by Geoff Zeiss

The source of the accelerating rise in atmospheric methane concentration since 2007 remains an open question. A recent study using satellite imagery suggests that the increase may be ascribed to increased fossil fuels and livestock sources in roughly equal measure.

Low cost sensor enables citizen scientists to measure and share urban air pollution data over the web

Posted on June 2, 2018August 10, 2019 by Geoff Zeiss

Based on the latest results from WHO air pollution is now the world’s largest single environmental health risk, linked to 12% of all global deaths. Citizen scientists can contribute to measuring air pollution using a low cost sensor measuring atmospheric particulate matter and share the measurements via open source geospatial web mapping software.

Decreasing oxygen in open ocean threatens biological diversity

Posted on January 12, 2018August 10, 2019 by Geoff Zeiss

Oxygen is fundamental to oceanic biological processes and its decline can cause major changes in ocean productivity and biodiversity. Over the past 50 years low oxygen zones in the open oceans have expanded by an area equivalent to half the size of Canada and hundreds of coastal sites now have low oxygen concentrations that limit the distribution and abundance of animal populations.

Evidence for sea level rise of 17 meters in less than 350 years

Posted on December 28, 2017August 10, 2019 by Geoff Zeiss

During the last deglaciation there was several episodes of rapid and substantial sea level rise. A recent study has found that during one of these, sea level rose by about 17 meters over a period that does not exceed 350 years, but could be as low as a century.

Greenhouse gas emissions from melting permafrost not yet significant

Posted on December 26, 2017August 24, 2019 by Geoff Zeiss

As the Earth warms, permafrost soils melt and this old carbon is released into the atmosphere as methane and CO2. Using radiocarbon dating of methane bubbles and soil organic carbon from lakes formed by melting thermafrost in Alaska, Canada, Sweden and Siberia combined with remote sensing it is found that methane and carbon dioxide releaed in the Arctic region during the past 60 years is much less than the CO2 contributed annually from anthropogenic and other sources.

From Our Files

Comparison of temperature and CO2 from Vostok ice cores

Close correlation of temperature and greenhouse gas concentrations over the last four glacial-interglacial cycles

In January 1998, a collaborative ice-drilling project between Russia, the United States, and France at the Russian Vostok revealed that over the past four cycles atmospheric concentration of carbon dioxide correlates closely with Antarctic air-temperature. The analysis also suggests a sequence of events that is characteristic of every termination; warming by orbital forcing, then increasing greenhouse gases, and followed by ice sheet melting and reduced albedo.

Southern Ocean warming preceded rising CO2 during the last deglaciation

Marine cores collected in the western tropical Pacific were used to compare the chronology of Southern Ocean warming near Antarctica and rising CO2 during the last deglaciation. The results provide evidence that the Southern Ocean off Antarctica warmed by ~2°C between 19,000 and 17,000 years before the present, about 1,000 years before the rise in atmospheric CO2.

Evidence of biological feedback driving warming at ice age terminations

It is known that orbital forcing is involved in glacial/deglacial cycles but is insufficient by itself to explain the glacial/deglacial cycles. This study argues that a biological feedback mechanism kicks in when a threshold is reached and together with orbital forcing results in the sustained and rapidly increasing CO2 and surface temperature of a deglaciation.

Simple rule accounts for onset of ice age deglaciations over the past three million years

A recent study has created a simple mathematical rule that can account for the timing of the onset of interglacials following ice ages over the past three million years. The rule is based on predictable long-term astronomical variations in the Earth’s orbit and tilt called Milankovitch cycles.