October Climate Science Roundup

Despite concerns that it might be blocked by the Trump administration, the Fourth National Climate Assessment report was recently released. This month’s climate science news is a mix of good and bad: peat bogs may be more resilient carbon sinks than we thought, forests can help us fight heat waves, and narwhals are helping us study glacier melt, but on the other hand, more glaciers may be at risk of melting and some climate scientists are facing gag orders from the government.

Climate Science Special Report – Fourth National Climate Assessment

The U.S. government released the first of two volumes of the Fourth National Climate Assessment. The report definitively states that climate change is man-made and stems from carbon dioxide emissions from burning fossil fuels: “it is extremely likely [ed note: meaning, 95-100 percent certainty] that human influence has been the dominant cause of the observed warming since the mid-20th century. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.”

Narwhal recruits track melting Arctic ice

In a cooperative arrangement meant to improve understanding of both narwhal behavior and melting glaciers, the data gathered by tagged narwhals will help inform where, how, and how fast relatively warm ocean waters are melting Greenland’s ice. Measuring the ocean near Greenland’s glaciers can be a major challenge by ship because of heavy sea ice and numerous icebergs — but narwhals spend their time feeding in these exact waters.

Government scientist blocked from talking about climate and wildfires

A U.S. Forest Service scientist who was scheduled to talk about the role that climate change plays in wildfire conditions was denied approval to attend the conference featuring fire experts from around the country. The travel denial follows reports that the EPA blocked three scientists from making presentations at a conference in Rhode Island featuring climate change.

Massive carbon sink may be more resilient than scientists thought

A new study finds that plants in carbon-rich European peat bogs are able to adapt to changes in temperature, precipitation, and other climate-related factors. As the environment changes, specific types of plants may die off and be replaced by new species—but the study suggests that the incoming species tend to be similar to the old ones, meaning the stability of the bog is preserved. Peat bogs and other wetland ecosystems house extensive stores of dead, carbon-rich organic matter underground and serve as an important carbon sink.

Forests minimize severe heat waves

Extensive, mature forest cover can mitigate the impact of severe heat waves, droughts and other weather extremes over large regions, according to new NOAA research. The research quantifies how historical conversion of native forests to cropland has influenced the frequency of hot and dry summers in the mid-latitudes of the United States and Europe. The effect appears to be less clear in the tropics.

Globe had 2nd warmest year to date, 4th warmest September on record

The average global temperature set in September 2017 was 1.40 degrees F above the 20th-century average of 59.0 degrees, the fourth highest for September in the 1880-2017 record. The year-to-date average temperature was 1.57 degrees F above the 20th-century average of 57.5 degrees. This was the second warmest for this period, 0.23 of a degree behind the record set in 2016. Nine of the 10 warmest January-September global temperatures have occurred since 2005, with 1998 as the only exception. Below-average sea ice persists at the poles.

New Greenland maps show more glaciers at risk

New maps of Greenland’s coastal seafloor and bedrock beneath its massive ice sheet show that two to four times as many coastal glaciers are at risk of accelerated melting as previously thought.

NASA pinpoints cause of Earth’s recent record carbon dioxide spike

A new NASA study provides space-based evidence that Earth’s tropical regions were the cause of the largest annual increases in atmospheric carbon dioxide concentration seen in at least 2,000 years. Researchers have concluded that impacts of El Niño-related heat and drought occurring in tropical regions of South America, Africa, and Indonesia were responsible for the record spike in global carbon dioxide.

Edited by Elizabeth Weinberg. Have a climate science tip? Send it to climate-science@350pdx.org.