Month: October 2017

Climate change to make volcanoes more climate disruptive

From the NATIONAL CENTER FOR ATMOSPHERIC RESEARCH/UNIVERSITY CORPORATION FOR ATMOSPHERIC RESEARCH and the “It’s models, all the way down” department.

Future volcanic eruptions could cause more climate disruption

Climate change reduces oceans’ ability to buffer impacts

BOULDER, Colo. — Major volcanic eruptions in the future have the potential to affect global temperatures and precipitation more dramatically than in the past because of climate change, according to a new study led by the National Center for Atmospheric Research (NCAR).

The study authors focused on the cataclysmic eruption of Indonesia’s Mount Tambora in April 1815, which is thought to have triggered the so-called “year without a summer” in 1816. They found that if a similar eruption occurred in the year 2085, temperatures would plunge more deeply, although not enough to offset the future warming associated with climate change. The increased cooling after a future eruption would also disrupt the water cycle more severely, decreasing the amount of precipitation that falls globally.

The reason for the difference in climate response between 1815 and 2085 is tied to the oceans, which are expected to become more stratified as the planet warms, and therefore less able to moderate the climate impacts caused by volcanic eruptions.

“We discovered that the oceans play a very large role in moderating, while also lengthening, the surface cooling induced by the 1815 eruption,” said NCAR scientist John Fasullo, lead author of the new study. “The volcanic kick is just that — it’s a cooling kick that lasts for a year or so. But the oceans change the timescale. They act to not only dampen the initial cooling but also to spread it out over several years.”

The research will be published Oct. 31 in the journal Nature Communications. The work was funded in part by the National Science Foundation, NCAR’s sponsor. Other funders include NASA and the U.S. Department of Energy. The study co-authors are Robert Tomas, Samantha Stevenson, Bette Otto-Bliesner, and Esther Brady, all of NCAR, as well as Eugene Wahl, of the National Oceanic and Atmospheric Administration.

—A detailed look at a deadly past—

Mount Tambora’s eruption, the largest in the past several centuries, spewed a huge amount of sulfur dioxide into the upper atmosphere, where it turned into sulfate particles called aerosols. The layer of light-reflecting aerosols cooled Earth, setting in motion a chain of reactions that led to an extremely cold summer in 1816, especially across Europe and the northeast of North America. The “year without a summer” is blamed for widespread crop failure and disease, causing more than 100,000 deaths globally.

To better understand and quantify the climate effects of Mount Tambora’s eruption, and to explore how those effects might differ for a future eruption if climate change continues on its current trajectory, the research team turned to a sophisticated computer model developed by scientists from NCAR and the broader community.

The scientists looked at two sets of simulations from the Community Earth System Model. The first was taken from the CESM Last Millennium Ensemble Project, which simulates Earth’s climate from the year 850 through 2005, including volcanic eruptions in the historic record. The second set, which assumes that greenhouse gas emission continue unabated, was created by running CESM forward and repeating a hypothetical Mount Tambora eruption in 2085.

The historical model simulations revealed that two countervailing processes helped regulate Earth’s temperature after Tambora’s eruption. As aerosols in the stratosphere began blocking some of the Sun’s heat, this cooling was intensified by an increase in the amount of land covered by snow and ice, which reflected heat back to space. At the same time, the oceans served as an important counterbalance. As the surface of the oceans cooled, the colder water sank, allowing warmer water to rise and release more heat into the atmosphere.

By the time the oceans themselves had cooled substantially, the aerosol layer had begun to dissipate, allowing more of the Sun’s heat to again reach Earth’s surface. At that point, the ocean took on the opposite role, keeping the atmosphere cooler, since the oceans take much longer to warm back up than land.

“In our model runs, we found that Earth actually reached its minimum temperature the following year, when the aerosols were almost gone,” Fasullo said. “It turns out the aerosols did not need to stick around for an entire year to still have a year without a summer in 1816, since by then the oceans had cooled substantially.”

—The oceans in a changed climate—

When the scientists studied how the climate in 2085 would respond to a hypothetical eruption that mimicked Mount Tambora’s, they found that Earth would experience a similar increase in land area covered by snow and ice.

However, the ocean’s ability to moderate the cooling would be diminished substantially in 2085. As a result, the magnitude of Earth’s surface cooling could be as much as 40 percent greater in the future. The scientists caution, however, that the exact magnitude is difficult to quantify, since they had only a relatively small number of simulations of the future eruption.

The reason for the change has to do with a more stratified ocean. As the climate warms, sea surface temperatures increase. The warmer water at the ocean’s surface is then less able to mix with the colder, denser water below.

In the model runs, this increase in ocean stratification meant that the water that was cooled after the volcanic eruption became trapped at the surface instead of mixing deeper into the ocean, reducing the heat released into the atmosphere.

The scientists also found that the future eruption would have a larger effect on rainfall than the historical eruption of Mount Tambora. Cooler sea surface temperatures decrease the amount of water that evaporates into the atmosphere and, therefore, also decrease global average precipitation.

Though the study found that Earth’s response to a Tambora-like eruption would be more acute in the future than in the past, the scientists note that the average surface cooling caused by the 2085 eruption (about 1.1 degrees Celsius) would not be nearly enough to offset the warming caused by human-induced climate change (about 4.2 degrees Celsius by 2085).

Study co-author Otto-Bliesner said, “The response of the climate system to the 1815 eruption of Indonesia’s Mount Tambora gives us a perspective on potential surprises for the future, but with the twist that our climate system may respond much differently.”

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The paper (open access): http://ift.tt/2ij7QDV

The amplifying influence of increased ocean stratification on a future year without a summer

  • J. T. Fasullo, R. Tomas, S. Stevenson, B. Otto-Bliesner, E. Brady & E. Wahl

Abstract

In 1816, the coldest summer of the past two centuries was observed over northeastern North America and western Europe. This so-called Year Without a Summer (YWAS) has been widely attributed to the 1815 eruption of Indonesia’s Mt. Tambora and was concurrent with agricultural failures and famines worldwide. To understand the potential impacts of a similar future eruption, a thorough physical understanding of the YWAS is crucial. Climate model simulations of both the 1815 Tambora eruption and a hypothetical analogous future eruption are examined, the latter occurring in 2085 assuming a business-as-usual climate scenario. Here, we show that the 1815 eruption drove strong responses in both the ocean and cryosphere that were fundamental to driving the YWAS. Through modulation of ocean stratification and near-surface winds, global warming contributes to an amplified surface climate response. Limitations in using major volcanic eruptions as a constraint on cloud feedbacks are also found.

via Watts Up With That?

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October 31, 2017 at 12:16PM

Russia Won’t Ratify Paris Agreement Unless Western Sanctions Are Lifted

Russian ratification of the Paris climate agreement is conditional on the lifting of Western sanctions against Russia.

The Russian government adviser on environmental issues issued this statement just days before the next UN Climate Conference takes place in Bonn early next week.

Moscow is reluctant to ratify the Paris deal because of pressure on the oil and gas industry which is responsible for much of Russia’s exports.

“In order for us to ratify the Paris agreement we first need to talk about the partial lifting of sanctions against our companies,” said Rashid Ismailov, head of the Russian government’s environmental expert group.

“Russian companies must have access to financial resources, as well as financial institutions and foreign funds, to implement reforms in the area of ​​the environment.”

Full story

see also: Russia ties ratification of Paris agreement to lifting of sanctions

via The Global Warming Policy Forum (GWPF)

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October 31, 2017 at 12:01PM

Majority Of Australians In Favour Of Quitting Paris Climate Deal For Cheaper Energy

A new poll suggests Australians are split on the prospect of Australia quitting the Paris accord on climate change if it brings cheaper power prices.

A Newspoll survey published by The Australian found 45 per cent of surveyed voters would be in favour of quitting the international agreement for cheaper bills, compared with 40 per cent who didn’t favour the move and 15 per cent who weren’t sure.

President Donald Trump pulled the US out of the Paris accord, which commits Australia to a 28 per cent reduction on 2005 emissions in the next 13 years, claiming the cost outweighed the benefit.

Full story

via The Global Warming Policy Forum (GWPF)

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October 31, 2017 at 11:17AM

Stormy Wind Price Collapse Reveals ‘Madness’ Of Germany’s Green Energy Transition

Autumn storm Herwart has caused chaos on the German energy market. Because of the strong wind, electricity prices collapsed into the negative. Consumers, however, won’t benefit from negative prices. For them, electricity is becoming even more expensive.

Storm ‘Herwart’ has caused extreme turbulences in Germany. Now it has been revealed that the storm last weekend not only uprooted trees, brought down roofs and paralysed train services. The gale-force gusts at speeds of up to 140 km per hour also caused chaos on the German energy market.

That is because ‘Herwart’ caused a lot of wind which in turn generated so much wind energy that the price of electricity almost collapsed. Within minutes the prices for electricity on the energy exchange EEX went down — the market was thrown upside down. Those who sold their electricity suddenly had to pay their customers. At the hight of the storm, the price dropped to minus 83.06 euros per megawatt hour. On average, the price was down to minus € 52.11, the lowest since Christmas 2012. At “normal” times electricity is traded for around 37 euros per megawatt hour – plus 37 euros.

In a rather sobering way Herwart shows the blatant flaws of Germany’s green energy transition. The latest collapse at the weekend may have been particularly manifest. Yet negative prices on Germany’s power exchanges have become part and parcel of everyday energy. Whenever German solar panels or wind turbines produce more energy than is needed, it comes to a glut of electricity and prices plummet.

The reason is the Renewable Energy Sources Act (EEG) which systematically eliminates market forces. Each producer of renewable electricity is allowed to feed their kilowatt hours into the grid, regardless of demand. Grid operators are required to take electricity at a fixed rate and trade surplus electricity on the EEX stock exchange. Private consumers do not benefit from the negative electricity prices, but have to pay even more.

If the prices on electricity exchanges are negative, the difference between the guaranteed rate and the market price and as a result the corresponding subsidy costs increase. This in turn leads to a rise of the renewable energy surcharge which must be paid by German households. This year, the surcharge has risen to a record high of 6.88 cents per kilowatt hour…

The profiteers of this negative price paradox are Germany’s neighboring countries. “They like to take our surplus electricity off and at the same time shut down their own power plants,” says industry expert Struck. Especially in countries like Switzerland and Austria, this method works splendidly. Operators of so-called pumped storage reservoirs in the high mountains fill their reservoirs with Germany’s free electricity. This practice works perfectly as electricity from foreign power plants is later sold back to Germany at lucrative prices.

Full story (in German)

via The Global Warming Policy Forum (GWPF)

http://ift.tt/2z070UB

October 31, 2017 at 10:49AM