Antarctica and the Southern Ocean in 2070, under low and high emissions scenarios

A team of experts in biology, oceanography, glaciology, geophysics, climate science and policy, analyzed the potential impacts of two different future scenarios of carbon emissions, RCP2.6 (low emission & strong action) and RCP 8.5 (high emission & weak action), on Antarctica and the Southern Ocean. The team assessed key systems including  global average air temperature; Antarctic contribution... Continue Reading →

Man-made nutrient pollution could make coral reefs more vulnerable to ocean acidification

A team of scientists from California State University and University of Hawaii carried out a series of laboratory experiments adding nitrate and phosphate to aquariums that contain the coral reef community (corals, seaweeds and dead reef rubble). Their experiments showed that in nutrient polluted seawater, the calcification by coral reefs became less effective disrupting the relationship between... Continue Reading →

Sustained climate warming drives declining marine biological productivity

In the Southern Ocean, nutrient-rich North Atlantic Deep Water upwells to the surface, and the northward surface water sinks at mid-depth (as Subantarctic Mode Water and Antarctic Intermediate Water) and transports nutrients into the low-latitude thermocline. According to a recent article appeared in Science, climate model simulations under RCP 8.5 scenario project that the Antarctic... Continue Reading →

Meridional overturning circulation conveys fast acidification to the deep Atlantic Ocean posing a severe threat to cold-water coral habitats.

Increasing atmospheric carbon dioxide concentrations are increasing the acidity of the oceans and reducing carbonate-ion concentrations, making it difficult for corals to maintain their calcium carbonate skeletons. This paper reports a roughly 40 per cent reduction in the transport of carbonate ions to the deep North Atlantic ocean since preindustrial times, with implications for cold-water... Continue Reading →

Ocean acidification affects coral growth by reducing skeletal density

Ocean acidification (OA) threatens coral reef futures by reducing the concentration of carbonate ions that corals need to construct their skeletons. However, quantitative predictions of reef futures under OA are confounded by mixed responses of corals to OA in experiments and field observations. We modeled the skeletal growth of a dominant reef-building coral, Porites, as a... Continue Reading →

Significant changes in the nutrient, carbon, and trace metal balances of the Arctic Ocean are underway

Rising temperatures in the Arctic Ocean region are responsible for changes such as reduced ice cover, permafrost thawing, and increased river discharge, which, together, alter nutrient and carbon cycles over the vast Arctic continental shelf. We show that the concentration of radium-228, sourced to seawater through sediment-water exchange processes, has increased substantially in surface waters... Continue Reading →

Explaining extreme events from a climate perspective

This special report of the Bulletin of the American Meteorological Society (BAMS) presents some extreme events in 2016, such as the record global heat, the heat across Asia, the 2015-16 El Niño and a marine heat wave off the coast of Alaska, and discusses how human-caused climate change may have affected the strength and likelihood of these extreme events.... Continue Reading →

Deep oceans may acidify faster than anticipated due to global warming

Oceans worldwide are undergoing acidification due to the penetration of anthropogenic CO2 from the atmosphere. The rate of acidification generally diminishes with increasing depth. Yet, slowing down of the thermohaline circulation due to global warming could reduce the pH in the deep oceans, as more organic material would decompose with a longer residence time. To... Continue Reading →

Highlights of the findings of the U.S. global change research program climate science special report

This executive summary presents the Fourth National Climate Assessment (NCA4), an authoritative assessment of the science of climate change, with a focus on the United States. This represents the first of two volumes of the Fourth National Climate Assessment, mandated by the Global Change Research Act of 1990. https://science2017.globalchange.gov/chapter/executive-summary/

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