Home » Posts tagged 'ocean acidification'
Tag Archives: ocean acidification
Surveying archaeologists across the globe reveals deeper and more widespread roots of the human age, the Anthropocene
Surveying archaeologists across the globe reveals deeper and more widespread roots of the human age, the Anthropocene
Examples of how human societies are changing the planet abound – from building roads and houses, clearing forests for agriculture and digging train tunnels, to shrinking the ozone layer, driving species extinct, changing the climate and acidifying the oceans. Human impacts are everywhere. Our societies have changed Earth so much that it’s impossible to reverse many of these effects.
Some researchers believe these changes are so big that they mark the beginning of a new “human age” of Earth history, the Anthropocene epoch. A committee of geologists has now proposed to mark the start of the Anthropocene in the mid-20th century, based on a striking indicator: the widely scattered radioactive dust from nuclear bomb tests in the early 1950s.
But this is not the final word.
Not everyone is sure that today’s industrialized, globalized societies will be around long enough to define a new geological epoch. Perhaps we are just a flash in the pan – an event – rather than a long, enduring epoch.
Others debate the utility of picking a single thin line in Earth’s geological record to mark the start of human impacts in the geological record. Maybe the Anthropocene began at different times in different parts of the world. For example, the first instances of agriculture emerged at different places at different times, and resulted in huge impacts on the environment, through land clearing, habitat losses, extinctions, erosion and carbon emissions, forever changing the global climate.
…click on the above link to read the rest of the article…
Acidification could leave oceans ‘uninhabitable’ for cold-water corals
Ocean acidification, which occurs as seawater takes up CO2 from the atmosphere, could threaten around 70% of cold-water coral living below 1,500 metres in the North Atlantic Ocean by 2050, the research finds.
Acidified waters that accumulate in the North Atlantic could then be circulated to the global seas via a system of ocean currents, the lead author tells Carbon Brief, which could have consequences for reefs across the world.
The findings reiterate how many coral reefs could “dissolve” and “crumble” as the world continues to warm, another scientist tells Carbon Brief.
Cool corals
Cold-water corals are found in deep, dark parts of the world’s oceans in both the northern and southern hemisphere. They can thrive at depths of up to 2,000 metres and in water temperatures as low as 4C.
Unlike tropical corals, cold-water corals do not rely on colourful algae for their food. Instead, cold-water coral feed on floating plankton.
This means they are unaffected by coral bleaching, a process which is heightened by climate change and poses a great threat to the survival of tropical reefs, such as the Great Barrier Reef.
However, both tropical and cold-water coral species are threatened by a process known as “ocean acidification”, which occurs as seawater absorbs CO2 from the atmosphere.
The oceans have absorbed around 30% (pdf) of the CO2 released by human activity since the industrial revolution. This has caused oceans, which are alkaline, to become more acidic over time. The overall pH of seawater has fallen from around 8.2 to 8.1from pre-industrial times to the present day.
…click on the above link to read the rest of the article…
Shrimps sound ocean acidity alarm
Shrimps sound ocean acidity alarm
The snapping shrimp is the noisiest marine creature in coastal ecosystems.
Image: Tullio Ross/University of Adelaide
Sustainability Metrics, Growth Limits, and Philanthropy
Sustainability Metrics, Growth Limits, and Philanthropy
As the metrics of sustainability become ever more robust and sophisticated, it is ever more apparent to many of us who study those metrics that industrial civilization, as currently configured, is unsustainable.
Ecological footprint analysis tells us that we are presently using 1.5 Earths’ worth of resources annually. We are able to do this only by drawing down renewable resources at a rate that exceeds their ability to regenerate; in other words, by stealing from the future.
Planetary Boundaries analysts have identified nine crucial parameters that define a safe operating space for humanity within the global ecosystem. We are currently operating outside that safety zone with regard to four of the boundaries. Exceeding just one boundary far enough, long enough, imperils both human society and the ecosystem on which it necessarily depends.
The most widely discussed of those boundaries is the planetary carbon budget. As we all know only too well, the CO2 content of the atmosphere now exceeds 400 parts per million—up from the pre-industrial level of 280ppm—and we appear to be well on our way to 450, 550, or even 650ppm, while climate scientists have determined that 350 ppm is the safe limit.
Those numbers, plus extinction rates, rates of ocean acidification, rates of topsoil erosion, and rates of deforestation, are the metrics of sustainability that tend to be most frequently discussed by environmentalists, and the alarming numbers being reported for these indices are certainly sufficient to support my opening assertion that current industrial society is unsustainable. However there are two other important metrics that have fallen out of fashion, largely because many people assume they measure society’s health rather than its vulnerability. One is human population growth. We all love humanity, but how much of it can the Earth support? World population stands at about 7.3 billion, and is on course to reach between 9 and 11 billion later this century. Yet a growing human population makes all those previously mentioned ecological perils—including climate change, deforestation, loss of biodiversity, and soil degradation—harder to address.
…click on the above link to read the rest of the article…
Who Stands To Benefit From Climate Change?
Who Stands To Benefit From Climate Change?.
The Intergovernmental Panel on Climate Change (IPCC) released their synthesis report Sunday, Nov. 2nd. The report combines the Panel’s past work and reiterates the near unanimity in the scientific community regarding the man-made role in global climate change. Still, public and political perception is very much divided and the report aims to lay the foundation for a new global treaty on climate change by the end of next year. Stark in their assessment, the IPCC posits a grim future in the absence of any meaningful mitigation. Not all change is bad however, and, when examining the energy implications, global climate change produces its share of winners.
According to the Panel, the most recent 30-year period was likely the warmest of the last 1,400 years. Nowhere is that more apparent than in the oceans. Between 1971 and 2010, more than 90 percent of the energy accumulated in the climate system was stored in the ocean. Since the beginning of the industrial era, ocean acidification is up 26 percent and Arctic and sub-Arctic ice sheets have continued to shrink, increasing the rate of sea level rise worldwide. On land, spring snow cover has decreased in extent globally and permafrost temperatures have increased in most regions.
Globally averaged combined land and ocean surface temperatures, Source: IPCC
…click on the above link to read the rest of the article…
