July Climate Science News Roundup

Calving icebergs at both poles, eutrophication in our coastal ecosystems: more often than not, the current climate science can seem dire. But by arming ourselves with the most up-to-date science, we can be more effective in changing the culture around climate change. This month’s climate science round-up seeks to provide accurate and effective information so that we can work together to save our planet.

Massive iceberg breaks off from Antarctica

An iceberg about the size of the state of Delaware split off from Antarctica’s Larsen C ice shelf sometime between July 10 and July 12. Larsen C is the fourth largest ice shelf ringing Antarctica. Now that the iceberg has broken away, the Larsen C shelf area has shrunk by approximately 10 percent. The growth of the crack is not directly linked to climate change, but the split may be indirectly linked through factors like warmer ocean waters eating away at the base of the shelf.

Forget that big iceberg–a smaller one in the Arctic is more troubling

Not long after an iceberg split off of Antarctica’s Larsen C ice shelf, a smaller one broke free in the Arctic. This one is comparatively small — about three times the size of Manhattan — but it has a much clearer link to climate change.

NOAA’s Greenhouse Gas Index up 40 percent since 1990

NOAA’s Annual Greenhouse Gas Index, which tracks the warming influence of long-lived greenhouse gases, has increased by 40 percent from 1990 to 2016 – with most of that attributable to rising carbon dioxide levels, according to NOAA climate scientists. The Annual Greenhouse Gas Index is a tool that helps policymakers, educators, and the public understand how greenhouse gases levels have affected the climate over time.

After 2000-era plateau, global methane levels hitting new highs

Though carbon dioxide is the most abundant greenhouse gas produced by human activities, methane traps more heat. Global methane levels “flatlined” from 1999 to 2006, but NOAA data show that in recent years global methane levels have been hitting new highs. Researchers are still working to figure out the cause of this increase, but most of the data point to either agriculture or wetlands in the tropics as the source.

Arctic winter warming events becoming more frequent, longer-lasting

Arctic winter warming events – winter days where temperatures peak above 14 degrees Fahrenheit (minus 10 degrees Celsius) – are a normal part of the climate over the ice-covered Arctic Ocean. But new research by an international team finds these events are becoming more frequent and lasting longer than they did three decades ago. A new study, published in Geophysical Research Letters on Jul. 10, shows that since 1980, an additional six warming events are occurring each winter in the North Pole region. The study also shows that the average length of each event has grown from fewer than two days to nearly two and a half days.

Nitrogen stewardship in the Anthropocene

Increased precipitation resulting from climate change is increasing eutrophication near coastlines. Rainfall washes nitrogen compounds, mainly from agriculture and sewage, into estuaries and coastal waters. This nitrogen fuels algal blooms, which can deprive ecosystems of oxygen when the algae decay, with sometimes extensive ecological and economic effects.

The world may have less time to address climate change than scientists thought

Countries in the Paris climate agreement set a target of keeping warming below 2 degrees Celsius by curbing carbon emissions compared to their preindustrial levels. But a new study shows that the preindustrial level used in the agreement, based on temperature records from the late 19th century, doesn’t account for a potential century of rising temperatures caused by carbon dioxide emissions. Accounting for those gases, released from about 1750 to 1875, would add another one-fifth of a degree to the baseline temperature, the study found.

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