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A new NASA

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climate simulation suggests
that extremely large volcanic eruptions

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called flood basalt eruptions
can significantly warm Earth's climate

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and devastate

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the ozone layer that shields life
from the sun's ultraviolet radiation.

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Unlike brief, explosive volcanic eruptions
that occur over hours or days,

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flood basalts are regions
with a series of eruptions, perhaps

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centuries each, and occurring
over periods of hundreds

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to thousands of years,
sometimes even longer.

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Some happen at about the same time
as mass extinction events, and many

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are associated with extremely warm
periods in Earth's history.

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Researchers used the Goddard Earth
Observing System Chemistry Climate Model

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to simulate one such flood
basalt eruption.

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The four year
long phase of the Columbia River basalt

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that occurred between 15 to 17 million
years ago in the Pacific Northwest,

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the model

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calculated the effects of the eruption
on the troposphere,

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the lowest layer of the atmosphere
with most of the water vapor and weather

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and the stratosphere
that is mostly dry and calm.

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Scientists expected to see intense
cooling in simulations.

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However, they found that a brief cooling
period of about two years

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was overwhelmed
by an intense warming effect.

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In the simulation,
the Amazon and East Central Australia

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reached monthly mean temperatures
of 49 degrees

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Celsius in the Arabian Peninsula.

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July mean temperatures were equal to
or exceeded

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55 degrees Celsius

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in the central United States.

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There were extreme
monthly mean temperatures equal to

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or exceeding 40 degrees Celsius

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the simulations
predicted a reduction in the ozone

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by about two thirds over
global average values,

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which is roughly equivalent
to the whole planet

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having an ozone thinning comparable
to a severe Antarctic ozone hole.

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Eruptions emit

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sulfur dioxide gas into the atmosphere

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which converts to solid sulfate aerosols.

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These aerosols reflect visible sunlight,

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which causes the initial cooling effect

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but also absorb infrared radiation,

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which warms the upper atmosphere.

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In the simulation,
most portions of the atmosphere

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were almost completely opaque to the sun.

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Warming this region of the atmosphere
allows water vapor

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that's usually near the surface
to get mixed into the dry stratosphere.

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Water vapor is a greenhouse gas that emits
infrared radiation to warm the planet.

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In the simulation,
there was a 10000% increase

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in stratospheric water vapor

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These flood basalt eruptions
also appear to have been common on other

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terrestrial worlds in our solar system,
such as Mars and Venus.

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Although Mars and Venus
may have had oceans of water

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in the distant past,
both are currently very dry.

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Scientists
are investigating how these worlds lost

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most of their water
to become inhospitable for life.

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And if the predictions of this simulation
are correct, extensive flood

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basalt eruptions could have contributed
to their arid fates.