Anthropogenic Climate Change

Migrating 'supraglacial' lakes could trigger future Greenland ice loss: "Predictions of Greenland ice loss and its impact on rising sea levels may have been greatly underestimated. Supraglacial lakes are darker than ice, so they absorb more of the Sun's heat, which leads to increased melting. When the lakes reach a critical size, they drain through ice fractures, allowing water to reach the ice sheet base which causes it to slide more quickly into the oceans. These changes can also trigger further melting."

Past global warming similar to today's: Size, duration were like modern climate shift, but in two pulses: "The rate at which carbon emissions warmed Earth's climate almost 56 million years ago resembles modern, human-caused global warming much more than previously believed, but involved two pulses of carbon to the atmosphere, University of Utah researchers and their colleagues found.

The findings mean the so-called Paleocene-Eocene thermal maximum, or PETM, can provide clues to the future of modern climate change. The good news: Earth and most species survived. The bad news: It took millennia to recover from the episode, when temperatures rose by 5 to 8 degrees Celsius (9 to 15 degrees Fahrenheit).

'There is a positive note in that the world persisted, it did not go down in flames, it has a way of self-correcting and righting itself,' says University of Utah geochemist Gabe Bowen, lead author of the study published today in the journal Nature Geoscience. 'However, in this event it took almost 200,000 years before things got back to normal.'"

Cost of cloud brightening for cooler planet revealed: "Scientists have identified the most energy-efficient way to make clouds more reflective to the sun in a bid to combat climate change. Marine Cloud Brightening is a reversible geoengineering method proposed to mitigate rising global temperatures. It relies on propelling a fine mist of salt particles high into the atmosphere to increase the albedo of clouds — the amount of sunlight they reflect back into space."

NASA satellites measure increase of Sun's energy absorbed in the Arctic: "NASA satellite instruments have observed a marked increase in solar radiation absorbed in the Arctic since the year 2000 - a trend that aligns with the steady decrease in Arctic sea ice during the same period.

While sea ice is mostly white and reflects the sun's rays, ocean water is dark and absorbs the sun's energy at a higher rate. A decline in the region's albedo - its reflectivity, in effect - has been a key concern among scientists since the summer Arctic sea ice cover began shrinking in recent decades. As more of the sun's energy is absorbed by the climate system, it enhances ongoing warming in the region, which is more pronounced than anywhere else on the planet."

Climate change could slash coffee production: "Half of the land needed for coffee production could disappear by 2050. That's the takeaway of a new modeling study, which estimates how climate change will alter conditions such as temperature and precipitation that coffee beans grow in."

'Tipping points' for sea level rise related flooding determined: "By 2050, a majority of US coastal areas are likely to be threatened by 30 or more days of flooding each year due to dramatically accelerating impacts from sea level rise, according to a new study."

Coral reveals long-term link between Pacific winds, global climate: "New research indicates that shifts in Pacific trade winds played a key role in twentieth century climate variation, a sign that they may again be influencing global temperatures."

Less tasty shrimp, thanks to climate change: "Climate change won’t just harm marine life—it could also affect how it tastes. A new study finds that as oceans become more acidic—thanks to the carbon dioxide emissions they suck up—they will sour the flavor of shrimp. Researchers took hundreds of northern shrimp (Pandalus borealis, pictured) and put them in tanks with water either of current acidity (pH 8) or projected acidity for 2100 (pH 7.5). The waters were 11°C, at the higher end of the range that shrimp can normally tolerate. The researchers chose that temperature to put their bodies under stress and thus make acidification’s effects stand out more. After 3 weeks, the team counted the number of surviving shrimp and did a taste test with 30 connoisseurs. Shrimp from less acidic waters were 3.4 times as likely to be judged the tastiest, while those from more acidic waters were 2.6 times as likely to be rated the worst tasting. Moreover, shrimp in the more acidic waters were 1.6 times as likely to die, the researchers reported last month in the Journal of Shellfish Research."

NASA finds good news on forests and carbon dioxide: "A new NASA-led study shows that tropical forests may be absorbing far more carbon dioxide than many scientists thought, in response to rising atmospheric levels of the greenhouse gas. The study estimates that tropical forests absorb 1.4 billion metric tons of carbon dioxide out of a total global absorption of 2.5 billion — more than is absorbed by forests in Canada, Siberia and other northern regions, called boreal forests."

Which fossil fuel reserves must stay in the ground to avoid dangerous climate change?: "A third of oil reserves, half of gas reserves and over 80% of current coal reserves globally should remain in the ground and not be used before 2050 if global warming is to stay below the 2°C target agreed by policy makers, according to new research."

Ancient fossils reveal rise in parasitic infections due to climate change: "When seeking clues about the future effects of possible climate change, sometimes scientists look to the past. Now, a paleobiologist from the University of Missouri has found indications of a greater risk of parasitic infection due to climate change in ancient mollusk fossils. His study of clams from the Holocene Epoch (that began 11,700 years ago) indicates that current sea level rise may mimic the same conditions that led to an upsurge in parasitic trematodes, or flatworms, he found from that time. He cautions that an outbreak in human infections from a related group of parasitic worms could occur and advises that communities use the information to prepare for possible human health risks."

Greenland meltwater contributes to rising sea levels: "As the largest single chunk of melting snow and ice in the world, the massive ice sheet that covers about 80 percent of Greenland is recognized as the biggest potential contributor to rising sea levels due to glacial meltwater."

Acceleration in sea level rise far larger than initially thought, study shows: "The acceleration in global sea level from the 20th century to the last two decades has been significantly larger than scientists previously thought, according to a new Harvard study.

The study, co-authored by Carling Hay, a post-doctoral fellow in the Department of Earth and Planetary Sciences (EPS), and Eric Morrow, a recent PhD graduate of EPS, shows that previous estimates of global sea-level rise from 1900-1990 had been over-estimated by as much as 30 percent. The report, however, confirms previous estimates of sea-level change since 1990, suggesting that the rate of sea-level change is increasing more quickly than previously believed. The new work is described in a January 14 paper published in Nature."

edited 14th Jan '15 6:53:43 PM by rmctagg09

NASA, NOAA find 2014 warmest year in modern record: "The year 2014 ranks as Earth's warmest since 1880, according to two separate analyses by NASA and National Oceanic and Atmospheric Administration (NOAA) scientists. The 10 warmest years in the instrumental record, with the exception of 1998, have now occurred since 2000. This trend continues a long-term warming of the planet, according to an analysis of surface temperature measurements."

Two lakes beneath the ice in Greenland, gone within weeks: "Researchers who are building the highest-resolution map of the Greenland Ice Sheet to date have made a surprising discovery: two lakes of meltwater that pooled beneath the ice and rapidly drained away.

One lake once held billions of gallons of water and emptied to form a mile-wide crater in just a few weeks. The other lake has filled and emptied twice in the last two years.

Researchers at The Ohio State University published findings on each lake separately: the first in the open-access journal The Cryosphere and the second in the journal Nature.

Ian Howat, associate professor of earth sciences at Ohio State, leads the team that discovered the cratered lake described in The Cryosphere. To him, the find adds to a growing body of evidence that meltwater has started overflowing the ice sheet's natural plumbing system and is causing 'blowouts' that simply drain lakes away."

Chris Mooney: The Midwest’s climate future: Missouri becomes like Arizona, Chicago becomes like Texas: “The bipartisan trio of climate risk prognosticators for the business community–Michael Bloomberg… Hank Paulson, and… Tom Steyer–are back…. A higher prevalence of extremely hot temperatures could severely impact corn and wheat production, the report warns, unless we take serious evasive action…. By 2100… the more likely range for losses, says the document, is 11 to 69 percent…"

Arctic ice cap slides into the ocean: "Satellite images have revealed that a remote Arctic ice cap has thinned by more than 50 metres since 2012 — about one sixth of its original thickness — and that it is now flowing 25 times faster. The findings show that over the last two decades, ice loss from the south-east region of Austfonna, located in the Svalbard archipelago, has increased significantly. In this time, ice flow has accelerated to speeds of several kilometres per year, and ice thinning has spread more than 50km inland — to within 10km of the summit."

Study yields surprising insights into the effects of wood fuel burning: "The harvesting of wood to meet the heating and cooking demands for billions of people worldwide has less of an impact on global forest loss and carbon dioxide (CO2) emissions than previously believed, according to a new Yale-led study.

Writing in the journal Nature Climate Change, a team of researchers, including Prof. Robert Bailis of the Yale School of Forestry & Environmental Studies (F&ES), concludes that only about 27 to 34 percent of wood fuel harvested worldwide would be considered 'unsustainable.' According to the assessment, 'sustainability' is based on whether or not annual harvesting exceeds incremental re-growth.

The other authors are Rudi Drigo, an independent forestry specialist with international experience; and Adrian Ghilardi and Omar Masera of the National Autonomous University of Mexico.

According to the authors, the findings point to the need for more nuanced, local-specific policies that address forest loss, climate change, and public health. They also suggest that existing carbon offset methodologies used to reduce carbon emissions likely overstate the CO2 emission reductions that can be achieved through the promotion of more efficient cookstove technologies."

So, once again I've come across someone writing that climate change can result in more frequent earthquakes. Is this actually true? I can see climate change affecting crop yields and causing sea level rise, but it affecting plate tectonics seems to be a bit unlikely.

That doesn't make sense.

What might happen though is a concurrent rise in earthquakes due to fracking with atmospheric CO 2 due to burning the natural gas that's produced by fracking.

The idea that global warming affects tectonics does exist, actually. As ice sheets melt the unloading of the underlying plate can favour the formation of volcanoes on it, and presumably affect the tectonics and earthquakes. Likewise, changes in sea level can affect island volcanoes by changes of climate and buoyancy.

Hmm, I guess there is the rebound effect from removing glaciers. I don't know much about it though, I admit.

And could you explain the island volcano thing?

Regarding island volcanoes, one concern is that increasing rainfall (and perhaps buoyancy effects) can effectively destabilize the volcano, favouring large scale landslides. They are very frequent on volcanoes in general but their effects are not well known. Depending upon which simulation you use (and which starting conditions) they can either threaten the island population or the entire ocean they are in.

Warm ocean melting East Antarctica's largest glacier: "The largest glacier in East Antarctica, containing ice equivalent to a six-metre (20-foot) rise in global sea levels, is melting due to warm ocean water, Australian scientists said on Monday.

The 120-kilometre (74.4 mile) long Totten Glacier, which is more than 30 kilometres wide, had been thought to be in an area untouched by warmer currents.

But a just-returned voyage to the frozen region found the waters around the glacier were warmer than expected and likely melting the ice from below."

Global warming won't mean more storms: Big storms to get bigger, small storms to shrink, experts predict: "Atmospheric physicists predict that global warming will not lead to an overall increasingly stormy atmosphere, a topic debated by scientists for decades. Instead, strong storms will become stronger while weak storms become weaker, and the cumulative result of the number of storms will remain unchanged."

Iceland rises as its glaciers melt from climate change: "Earth's crust under Iceland is rebounding as global warming melts the island's great ice caps. In south-central Iceland some sites are moving upward as much as 1.4 inches (35 mm) per year. A new paper is the first to show the current fast uplift of the Icelandic crust is a result of accelerated melting of the island's glaciers and coincides with the onset of warming that began about 30 years ago, the researchers said."

edited 29th Jan '15 10:06:26 PM by rmctagg09

Smothered oceans: Extreme oxygen loss in oceans accompanied past global climate change: "From the subarctic Pacific to the Chilean margins, extreme oxygen loss is stretching from the upper ocean to about 3,000 meters deep. In some oceanic regions, such loss occurred within 100 years or less, according to a new study."

Climate models don't over-predict warming, study shows: "If you listen to climate change skeptics, Earth's surface hasn't warmed appreciably in the last 15 years, and any "record" set last year is just the result of the planet doing what the planet naturally does.

It turns out they're right, but for the wrong reasons, according to a study published online Wednesday in the journal Nature.

There is no inherent bias in climate models that makes them over-estimate the effects of human activity, according to the study.

'Cherry picking' the most recent 15-year interval to refute climate change modeling is misleading and obscures the long-term agreement between the models and measurements, according to study co-author Piers Forster, an atmospheric physicist from the University of Leeds, England."

Heat waves becoming more prominent in urban areas, research reveals: "The world's urban areas have experienced significant increases in heat waves over the past 40 years, according to new research. These prolonged periods of extreme hot days have significantly increased in over 200 urban areas across the globe between 1973 and 2012, and have been most prominent in the most recent years on record."