Global Warming

Climate Change Could Make Common Clouds Extinct, Which Would Scorch the Planet

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If humanity pumps enough carbon dioxide into the atmosphere, one of Earth’s most important types of cloud could go extinct. And if the stratocumulus clouds — those puffy, low rolls of vapor that blanket much of the planet at any given moment — disappear, Earth’s temperature could climb sharply and radically, to heights not predicted in current climate models. That’s the conclusion of a paper published today (Feb. 25) in the journal Nature Geoscience.

Clouds have long been one of the great uncertainties of climate models. Clouds are complicated, small and fast-changing. Computer models that easily capture the complexity and detail of most climate systems just aren’t powerful enough to predict worldwide shifts in cloud behavior.

But clouds are important. They dye a wide swath of the atmosphere white, as seen from space, reflecting sunlight away from Earth’s surface. And stratocumulus clouds are an important part of that picture; they’re those white blankets you might have seen as you looked out the window of an airplane, rolling out below you and hiding the ground. Researchers suspect that certain sudden, past jumps in temperature may have been caused by changes to clouds like these.

And once the stratocumulus clouds are gone, Wolchover reported, they likely wouldn’t reappear until atmospheric carbon dioxide levels dropped below where they are currently.

Evidence for Man-Made Global Warming Hits ‘Gold Standard’

Evidence for man-made global warming has reached a “gold standard” level of certainty, adding pressure for cuts in greenhouse gases to limit rising temperatures, scientists said Monday.

“Humanity cannot afford to ignore such clear signals,” the U.S.-led team wrote in the journal Nature Climate Change of satellite measurements of rising temperatures over the past 40 years.

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

Nature – Images

Interesting Images

Awe-inspiring though it is, this is not a sight you want to see from your kitchen window.

This towering structure is known as a pyrocumulus cloud – a sure sign that a bushfire has morphed into a full firestorm, complete with its own devastating effects.

These firestorms create their own weather with lightning, strong winds, and even tornadoes that spread fire in multiple directions. These ingredients make them impossible for firefighters to put out.

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Nature – Images

Interesting Images

This perfectly symmetrical mushroom=shaped cloud was photographed by Gulf Shores, Alabama resident Rick Geiss from his local beach. This fluffy behemoth is actually a common type of storm cloud called a cumulus congestus.

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Nature – Images

Interesting Images

Lenticular clouds above Mount Shasta in northern California, USA. Interestingly, Mount Shasta has a long history of flying saucer visitations.

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Nature – Images

Interesting Images

Pyrocumulus Clouds: A dark, ominous cloud that formed over the massive Thomas Fire in Southern California is a pyrocumulus cloud, a special cloud that forms during fires.

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Nature – Images

Interesting Images

A gorgeous cloud phenomenon called von Kármán vortices paints the sky with a series of spirals in an image captured from space.

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Nature – Images

Interesting Images

A curling tongue of clouds reaches out to touch Portugal on the Iberian Peninsula in a new satellite image.

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Nature – Images

Interesting Images

Residents in Singapore were treated to a truly unusual phenomenon, as a so-called fire rainbow lit up the sky in the city-state. NASA says that fire rainbows are actually called circumhorizon arcs, which are created by a unique set of circumstances. A spokesman said: “The sun must be at least 58 degrees high in a sky where cirrus clouds are present. Furthermore, the numerous, flat, hexagonal ice-crystals that compose the cirrus cloud must be aligned horizontally to properly refract sunlight like a single gigantic prism. Therefore, circumhorizon arcs are quite unusual to see.”

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Global Warming

Climate Change May Already Be Shifting Clouds Toward the Poles

The way clouds cover the Earth may be changing because of global warming, according to a study published Monday that used satellite data to track cloud patterns across about two decades, starting in the 1980s.

Clouds in the mid-latitudes shifted toward the poles during that period, as the subtropical dry zones expanded and the highest cloud-tops got higher. These changes are predicted by most climate models of global warming.

About 70 percent of our planet is covered by clouds, at any given moment. These constantly moving shape-shifters aren’t exactly easy for scientists to study.

Clouds aren’t as simple as their fluffy nature might suggest. To understand them, scientists have to track the behaviour of tiny water droplets, as well as huge masses of clouds that might be hundreds of miles wide. And climate modellers also have to take into account the fact that clouds can have two different effects on temperatures.

During daytime, if there are a lot of clouds present, thick clouds, then that will keep the temperature cooler, because clouds reflect incoming sunlight back to space. But thick clouds can also act like a blanket that keeps the Earth’s warmth in, which is the reason why a cloudy night won’t be as cold at the surface as a clear night.

It’s probably happening primarily because of two influences — human-produced global warming, and also the recovery from the cooling effect of two volcanic eruptions during that time frame.

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Nature – Images

Interesting Images

Bright blue-white noctilucent clouds danced over the town of Nykøbing Mors in Denmark just before dawn.

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Nature – Images

Interesting Images

Flight Engineer Tim Peake of the European Space Agency photographed rare, high-altitude noctilucent or “night shining” clouds from the International Space Station on May 29, 2016.

Polar mesospheric clouds — also known as noctilucent clouds – form between 76 to 85 kilometres (47 to 53 miles) above the Earth’s surface, near the boundary of the mesosphere and thermosphere, a region known as the mesopause. At these altitudes, water vapour can freeze into clouds of ice crystals. When the sun is below the horizon and the ground is in darkness, these high clouds may still be illuminated, lending them their ethereal, “night shining” qualities.

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Global Warming

Global warming is pushing high altitude clouds towards the poles

A new Nasa analysis of 30-years of satellite data has revealed high altitude clouds shifting toward the poles are being moved by the expansion of the tropics. The changes could dramatically affect the planet’s climate, experts warn.

Where clouds are absent, darker surfaces like the ocean or vegetated land absorb heat, but where clouds occur their white tops reflect incoming sunlight away, which can cause a cooling effect on Earth’s surface.

The previous suggested reason was that climate change was shifting storms and the powerful air currents known as the jet streams – including the one that traverses the United States – toward the poles, which in turn were driving the movement of the clouds.

What they discovered was that the poleward shift of the clouds, which occurs in both the Northern and Southern Hemispheres, connected more strongly with the expansion of the tropics, defined by the general circulation Hadley cell, than with the movement of the jets.

The poleward shift of high altitude clouds affects how much sunlight reaches Earth’s surface because when they move, they reveal what’s below. The high altitude clouds clear to reveal dark ocean below – which absorbs incoming sunlight and causes a warming effect.

However, in the Southern Ocean around Antarctica, the high altitude clouds usually clear out of the way to reveal lower altitude clouds below – which continue to reflect sunlight from their white tops, causing little effect on the solar radiation reaching the surface.

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Global Warming

Cloud Study Suggests Global Warming May Be Worse Than Previously Believed

Climate models may have significantly miscalculated the effect of clouds in global warming, a new report revealed. This means future global temperatures could actually be worse than previously believed.

Researchers at Yale University examined a number of global climate projections, as well as satellite data. Studying the make-up of mixed-phase clouds, they found that clouds today actually hold more liquid, instead of ice.

Mixed-phase clouds typically consist of ice particles, liquid droplets, and water vapour. How is more liquid on clouds bad?

Clouds with more ice crystals are effective in reflecting sunlight than clouds with more liquid, acting as a shield to prevent too much light from the sun from reaching the Earth. Researchers said the more ice there is in clouds, the less warming there will be on the surface of the Earth.

Current climate models underestimate the role of clouds in global warming. Existing studies have over-estimated the prevalence of ice crystals in clouds, suggesting that global warming may be substantially worse than previously believed.

Nature – Images

Interesting Images: Nacreous Clouds

Clouds in the stratosphere are very rare. Yet for the past week they have been seen every day. Yesterday, Feb 2nd, Sean Crane of Harrogate UK hopped out of his bath to photograph the display:

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These fantasticaly-colored clouds are floating more than 80,000 feet above Earth’s surface. Normally, the thin air up there is crystal clear. Not this week. Water molecules are crystalizing in the lower stratosphere and the resulting ice crystals are assembling into polar stratospheric clouds (PSCs).

Also known as “nacreous” clouds, PSCs form in the lower stratosphere when temperatures drop to a staggeringly-cold -85ºC. High-altitude sunlight shining through tiny ice particles ~10µm wide produce bright iridescent colors by diffraction and interference.

Because these clouds require extreme cold, they are most often seen around the Arctic Circle. In recent days, however, they have been spotted as far south as the UK.


Clouds Over Southern Ocean Made by Ocean Creatures

The Southern Ocean is reckoned as the cloudiest region in our planet and it almost nearly blanketed all through the year. But it might be surprising that it is the tiny marine organisms known as Phytoplankton that live in the stormy waters of the ocean that are responsible for creating these clouds.

Measuring how the gases and particles emitted by these tiny creatures entered the atmosphere to become cloud seeds was the subject of a recent study. This study was also the first large scale correlation between cloud formation and biological activity in the Southern ocean. Establishing that link constitutes a significant first move towards understanding the role played by clouds and the tiny particles of air known as aerosols in the context of climate change and climate modelling.

In climate models, aerosols and clouds constitute two important wild cards and comprehending their impact on climate gets further complex when we consider the question of how they interact with each other. Soot is a type of aerosol that comes from human activities, but we also have other natural aerosols like sulphate, sea spray and ammonium salts in the atmosphere. All these particles form the ‘seeds’ and water vapour condenses around these to become tiny droplets and turn into clouds.

Clouds can have a key role when we consider climate – but that role is complicated. The planet tends to get cooled by the low lying clouds that functions as reflectors and bouncing the solar radiation back to space. Higher clouds on the other hand tend to trap the heat and prop up warming. Climate models in the Southern Ocean have been pretty poor in capturing the influence of the clouds by estimating less reflected radiation than what actually exists. Scientists will have to understand more about aerosols that help in formation of the clouds and how they have impacted the climate over the past 2 centuries, to improve these models. But the task gets difficult for tracking in the absence of knowledge on the number of ‘natural’ aerosols present in the atmosphere before industrialisation began.

If concentration of aerosols were higher during the preindustrial times, then the impact from human perturbations to aerosols would be smaller.

This also brings into focus the Southern Ocean. Apart from being the cloudiest place on the planet, it is also one among the cleanest and relatively unharmed by human activity. That makes it the perfect laboratory for examining the interaction between cloud and aerosols.