Terrestrial Ecosystems

Lamont's Andy Juhl and a team of scientists working with the non-profit Riverkeeper conducted an unprecedented health check of the entire Hudson River system, starting at the headwaters high in the Adirondacks and going all the way to New York Harbor, where the river meets the ocean. They released their results today, giving the 315-mile-long Hudson River a spotty but mostly positive health report with some important insights.

Researchers have predicted that as the planet is warmed by human-produced CO2, plants may add to the emissions and amplify the warming. Now, the most comprehensive global study of its kind yet suggests that this effect has limits, and that increases in plant respiration may not be as big as previously estimated. It shows that rates of increase slow in an easily predictable way as temperatures mount, in every region of earth, from tropics to tundra.

In the years before the Syrian conflict erupted, the region’s worst drought on record set in across the Levant, destroying crops and restricting water supplies in the already water-stressed region. A new study shows that that drought, from 1998-2012, wasn’t just the most severe in a century of record-keeping—it was the Levant’s most severe drought in at least 500 years and likely more than 900 years.

The long history of severe droughts across Europe and the Mediterranean has largely been told through historical documents and ancient journals, each chronicling the impact in a geographically restricted area. Now, for the first time, an atlas based on scientific evidence provides the big picture, using tree rings to map the reach and severity of dry and wet periods across Europe and parts of North Africa and the Middle East year-by-year over the past 2,000 years.

Over 40 years, the scientists of the internationally renowned Lamont Tree Ring Lab have hiked the continents in search of tree-ring records. They have documented droughts that stretched for hundreds of years, dated historic earthquakes and volcanic eruptions, and found in trees around the world evidence of how the planet cooled and then started warming. The Lab has expanded dendrochronology’s capabilities and becme a global leader in research, training and technology.
 

A new study says that global warming has measurably worsened the ongoing California drought. While scientists largely agree that natural weather variations have caused a lack of rain, an emerging consensus says that rising temperatures may be making things worse by driving moisture from plants and soil into the air. The new study is the first to estimate how much worse: as much as a quarter. The findings suggest that within a few decades, continually increasing temperatures and resulting moisture losses will push California into even more persistent aridity. The study appears this week in the journal Geophysical Research Letters.