Worldwide sea levels have climbed since 1900 by some 1.5 millimeters a year, a pace that is unprecedented in at least 3,000 years and generally attributable to melting ice sheets and glaciers and also the expansion of the oceans as their temperatures warm. Since the middle of the 20th century the rate has gained speed, exceeding 3 millimeters a year since 1992.

In the South the pace has quickened further, jumping from about 1.7 millimeters a year at the turn of the 20th century to at least 8.4 millimeters by 2021, according to a 2023 study published in Nature Communications based on tidal gauge records from throughout the region. In Pensacola, a beachy community on the western side of the Florida Panhandle, the rate soared to roughly 11 millimeters a year by the end of 2021.

In the South the trajectories would fall within and in some places exceed NOAA’s “high” scenario, according to the Nature Communications study. Further acceleration in the region would go as far as to threaten national security and outpace adaptation measures, the report warned.

The data suggest that by 2050 the sea level rise in Florida would correspond with NOAA’s “intermediate,” “intermediate-high” and “high” scenarios, according to the study.

Researchers at the Woods Hole Oceanographic Institution want to dump 6,600 gallons of sodium hydroxide, otherwise known as caustic soda or lye, into the ocean off the coast of Cape Cod in an effort to slow climate change.

The unusual plan will likely face significant headwinds, not just from US regulators but from local fishing communities and environmentalists as well...

...critics remain skeptical and concerned about the possible risks involved.

A recent study has identified significant impacts of the Madden-Julian Oscillation (MJO) and El Niño Southern Oscillation (ENSO) on coral bleaching events in the Great Barrier Reef (GBR).

The Great Barrier Reef, spanning nearly 350,000 square kilometers along Australia’s northeast coast, is the largest coral ecosystem globally.

“I’d often heard in the media that during El Niño periods the GBR is more likely to experience bleaching. Then during 2022, the reef experienced mass bleaching during a La Niña period, and it was reported that La Niña should mean cooling in the GBR,” Gregory said.

“However, in my research, I had examined this relationship and not found a strong connection between the ENSO index and ocean temperatures in this region. This motivated me to understand other drivers that could be influential.”

“The MJO, as the leading driver of sub-seasonal weather variability, seemed like an important one to consider. While ENSO provides insight into the expected synoptic states, it lacks details of anticipated sub-seasonal weather variability at local scales.”

These findings underscore the need for comprehensive forecasting models that include both ENSO and MJO impacts to better predict and manage coral bleaching events.

The study is published in the journal Geophysical Research Letters.

Rensselaer researcher links aquatic deoxygenation with the broader stability of Earth’s systems

Oxygen is a fundamental requirement of life, and the loss of oxygen in water, also referred to as aquatic deoxygenation, is a threat to life at all levels. In fact, in research recently published in Nature Ecology and Evolution, Rensselaer Polytechnic Institute’s Associate Professor Kevin Rose, Ph.D. and his collaborators describe how ongoing deoxygenation presents a major threat to the stability of the planet as a whole.

“It’s important that aquatic deoxygenation be added to the list of Planetary Boundaries,” said Rose. “This will help support and focus global monitoring, research, and policy efforts to help our aquatic ecosystems and, in turn, society at large.”

Across all aquatic ecosystems, from streams and rivers, lakes, reservoirs, and ponds to estuaries, coasts, and the open ocean, dissolved oxygen (DO) concentrations have rapidly and substantially declined in recent decades. Lakes and reservoirs have experienced oxygen losses of 5.5% and 18.6% respectively since 1980. The oceans have experienced oxygen losses of around 2% since 1960 and, although that number is smaller, it represents a more geographically and volumetrically extensive mass. Marine ecosystems have also experienced substantial variability in oxygen depletion. For example, the midwaters off of Central California have lost 40% of their oxygen in the last few decades. The volumes of aquatic ecosystems affected by oxygen depletion have increased dramatically across all types.

A trio of physicists and oceanologists, two with the University of Cologne's Institute of Geophysics and Meteorology and the third with the GEOMAR Helmholtz Center for Ocean Research Kiel, all in Germany, has found via the CESM1 climate model that an extreme El Niño tipping point could be reached in the coming decades under current emissions.

The study by Tobias Bayr, Stephanie Fiedler and Joke Lübbecke is published in Geophysical Research Letters.

The El Niño‐Southern Oscillation (ENSO) is a climate phenomenon in which heat released in parts of the ocean into the atmosphere results in more rainfall in places like the western coast of North and South America and droughts in places like Canada and Africa. Over the past several years, weather watchers have noticed that ENSO events have become more extreme.

To find out if that might be the case, the researchers gathered historical data, as well as data from other research efforts describing possible weather impacts due to rising global temperatures, and fed it to the CESM1 model then ran it under increased-temperature scenarios. Current estimates suggest that an increase of 2.9°C will occur by 2100 if greenhouse gas emissions are not stopped.

SINGAPORE, July 15 (Reuters) - The United Nations' International Seabed Authority (ISA) will meet on Monday to consider new rules allowing firms to extract minerals from the ocean floor, despite mounting concerns about the economic and environmental risks.

Supporters say deep sea mining will help boost supplies of raw materials like cobalt and nickel, which are needed for the global energy transition, but critics say it could destroy ecosystems and disrupt migratory routes.

As many as 27 countries are calling for at least a temporary halt of activities, and Hawaii last week became the fourth Pacific U.S. state to issue a comprehensive ban.

Meeting in Kingston, Jamaica, until July 26, the 36-member ISA council will negotiate the latest draft of a long-awaited "mining code", designed to regulate the exploration and extraction of "polymetallic nodules" and other deposits on the ocean floor. [...]

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