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charlesarthur : clouds   2

Cloud loss could add 8 degrees to global warming • Quanta Magazine
Natalie Wolchover:
<p>A picture emerged of a brief, cataclysmic hot spell 56 million years ago, now known as the Paleocene-Eocene Thermal Maximum (PETM). After heat-trapping carbon leaked into the sky from an unknown source, the planet, which was already several degrees Celsius hotter than it is today, gained an additional 6 degrees. The ocean turned jacuzzi-hot near the equator and experienced mass extinctions worldwide. On land, primitive monkeys, horses and other early mammals marched northward, following vegetation to higher latitudes. The mammals also miniaturized over generations, as leaves became less nutritious in the carbonaceous air. Violent storms ravaged the planet; the geologic record indicates flash floods and protracted droughts. As Kennett put it, “Earth was triggered, and all hell broke loose.”

The PETM doesn’t only provide a past example of CO2-driven climate change; scientists say it also points to an unknown factor that has an outsize influence on Earth’s climate. When the planet got hot, it got really hot. Ancient warming episodes like the PETM were always far more extreme than theoretical models of the climate suggest they should have been. Even after accounting for differences in geography, ocean currents and vegetation during these past episodes, paleoclimatologists find that something big appears to be missing from their models — an X-factor whose wild swings leave no trace in the fossil record.

Evidence is mounting in favor of the answer that experts have long suspected but have only recently been capable of exploring in detail. “It’s quite clear at this point that the answer is clouds,” said Matt Huber, a paleoclimate modeler at Purdue University.</p>

Long, but so very worth your time.
climatechange  climatecrisis  clouds 
may 2019 by charlesarthur
Google Maps gets a new, 700-trillion-pixel cloudless satellite map • The Atlantic
Robinson Meyer:
<p><a href="">More than 1 billion people use Google Maps every month</a>, making it possibly the most popular atlas ever created. On Monday, it gets a makeover, and its many users will see something different when they examine the planet’s forests, fields, seas, and cities.

Google has added 700 trillion pixels of new data to its service. The new map, which activates this week for all users of Google Maps and Google Earth, consists of orbital imagery that is newer, more detailed, and of higher contrast than the previous version.

Most importantly, this new map contains fewer clouds than before—only the second time Google has unveiled a “cloudless” map. Google had not updated its low- and medium-resolution satellite map in three years.

The improvements can be seen in the new map’s depiction of Christmas Island. Almost a thousand miles from Australia, the island was largely untouched by human settlement until the past two centuries. Its remoteness gives it a unique ecology, but—given its location in the middle of the tropical Indian Ocean—it is frequently obscured by clouds. The new map clears these away.</p>
maps  google  detail  clouds 
june 2016 by charlesarthur

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