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Posts Tagged ‘Global Warming’

Global Dimming and Death of Our Sun

Posted by jase on July 10, 2009

by Brian Cox

The Sun is Dying

Sol, our sun, will not live forever. It has enough fuel left, if our current understanding is correct, for another 5 billion years, at which point it will die. But could it be possible for the Sun to die much sooner, within the next 100 years even? From a scientific perspective, it should be said that this is very unlikely. But, it is also true that there is a lot about the universe that we do not understand.

Over the last few years astronomers have observed that there is extra “stuff” in the universe that we can see only by its gravitational influence on stars and galaxies. This stuff goes by the name of Dark Matter, and there is five times as much Dark Matter in the universe as there is normal matter, the stuff that makes up you, me, and the stars and planets we can see with our telescopes. What is this mysterious stuff? It’s possible, some scientists would say likely even, that this stuff is made of particles known as supersymmetric particles, a new and exotic form of matter that is high on the list of potential discoveries at CERN’s giant Large Hadron Collider, a 27km in circumference machine which begins operations this year after almost a decade of construction.

Theoretical physicists have spent many years calculating the properties of these supersymmetric particles, and we have a reasonable theoretical understanding of how they might behave. One possibility is that they could clump together into giant balls known as Q-balls. If this is true, then these heavy and exotic objects could have been made billionths of a second after our Universe began, and still be roaming the Universe today. It is speculated that, if a Q-ball drifts into the heart of a super-dense object such as a neutron star, it could begin to eat away at it’s core like a cancer, until the star is no longer massive enough to maintain itself and explodes in a violent explosion. Such explosions, known as gamma ray bursts, are seen in the Universe, although their cause is as yet unknown.

Could such a dangerous, exotic object drift into the Sun’s core and cause it to stop shining? It is likely that the Sun is many times too diffuse to stop a Q-ball – it would power right through. But maybe, just maybe, some strange exotic form of matter from the earliest times in the universe could settle deep within the Sun’s core, and disrupt its function enough to cause the catastrophic scenario seen in Sunshine. It’s far-fetched, but we have a saying in physics that anything that isn’t explicitly ruled out is therefore possible, so in the final analysis, you never quite know.

Global Dimming 

It is now suspected that pollution in the Earth’s atmosphere, caused by industrialization and natural phenomena such as volcanic eruptions, may have significantly reduced that amount of sunlight reaching the Earth’s surface. It is estimated that this could have led to a cooling effect of over 1 degree overt he last 40 years, which would go some way to offsetting the effect of global warming. Global warming is caused primarily by increasing carbon dioxide levels in the atmosphere that prevent heat being radiated back out into space from the Earth’s surface.

The phenomenon of global dimming may therefore have saved us, so far, from the worst affects of climate change, although it has been noticed that as pollution levels have been reduced, particularly in Western Europe, the affects of global dimming seem to be reducing, leading to an accelerating temperature rise once again. We may therefore be in the paradoxical situation that reducing pollution might INCREASE the effects of global warming, leading us ever more quickly towards catastrophe.

This discovery isn’t all bad, however, because it may suggest a short term solution to climate change. Why not intentionally put pollutants, which may be designed to be benign in other respects, into the atmosphere to accelerate global dimming, and therefore slow the climate change caused by carbon dioxide emissions. Several suggestions along these lines have been made, including adding small particles to airplane fuel, and therefore using one of the main contributors to climate change, aircraft, to slow its effects. It’s an intriguing possibility, and one that is the focus of significant research, although it should be said that we cannot at present predict the effects of such fine-tuning of the climate, so global dimming shouldn’t be seen as a means to allow us to continue to increase carbon dioxide emissions.

Posted in Astronomy, Climate, Earth, extinction, Global Warming, Science, Solar Energy, Space | Tagged: , , , , , , , , , , , | Leave a Comment »

Global Warming Shrinking Sheep

Posted by jase on July 6, 2009

Changing winter conditions are causing Scotland’s wild Soay sheep to get smaller, according to a study that suggests climate change can trump natural selection.

The authors of the study published in “Science” believe that it highlights how wide-ranging the effects of global climate change can be, adding further complexity to the changes we might expect to see in animal populations in future.

“It’s only in the last few years that we’ve realized that evolution can influence species’ physical traits as quickly as ecological changes can. This study addresses one of the major goals of population biology, namely to untangle the ways in which evolutionary and environmental changes influence a species’ traits,” said Andrew Sugden, deputy and international managing editor at Science.

The researchers analyzed body-weight measurements and life-history data for the female members of a population of Soay sheep. The sheep live on the island of Hirta in the St. Kilda archipelago of Scotland and have been studied closely since 1985.

They selected body size because it is a heritable trait, and because the sheep have, on average, been decreasing in size for the last 25 years.

According to the findings lambs are not growing as quickly as they once did as winters have become shorter so do not need to put on as much as weight in the first months of life to survive.

The results suggest that the decrease is primarily an ecological response to environmental variation over the last 25 years. Evolutionary change, the report says, has contributed relatively little.

“Sheep are getting smaller. Well, at least the wild Soay sheep living on a remote Scottish island are. But according to classic evolutionary theory, they should have been getting bigger, because larger sheep tend to be more likely to survive and reproduce than smaller ones, and offspring tend to resemble their parents,” said study author Tim Coulson of Imperial College London.

“Our findings have solved a paradox that has tormented biologists for years — why predictions did not match observation. Biologists have realized that ecological and evolutionary processes are intricately intertwined, and they now have a way of dissecting out the contribution of each. Unfortunately it is too early to tell whether a warming world will lead to pocket-sized sheep,” said Coulson.

Posted in Animals, Biology, Climate, Earth, Global Warming, Science | Tagged: , , , , , , , , | 1 Comment »

What Temperature is the Earth Supposed to Be?

Posted by jase on June 28, 2009

If we don’t get our act together and slash greenhouse gas emissions, the UN climate change panel tells us, average global temperatures could rise by as much as 10 degrees F. by the end of the century.

But would that really be so bad? Sure, much of the South would be unbearable during the summer months (as would many of those tropical countries), but think of all that beautiful real estate in Alaska that we’d open up! And many of us here in Boston would willingly trade a dozen or more 100-degree F. days each year to wear shorts and flip-flops through October. Less snow shoveling, more Frisbee tossing. What’s not to like?

Who decreed that average global surface temperatures have to stay at the 58 degrees F. or so that modern humans are used to? After all, we’ve experienced temperatures much higher than that in the past (by “we,” I mean multicellular organisms living a half-billion years ago), and we’ve also had our share of ice ages. What is the “right” temperature for the planet?

Climate-change deniers love posing this question (economist Mark W. Hendrickson asked it earlier this week in a Monitor op-ed), because it makes those who try to answer it sound sentimental and unscientific. There is no “supposed to be” in nature. It is what it is.

But the question also misses the point: The alarming thing about global warming is not how high the average temperature will be, but how fast it’s rising.

And it’s rising really fast, compared to historical temperature shifts. The planet’s surface has warmed about 1.4 degrees F. since 1880, most of it in the past 30 years. And it’s accelerating. According to Britain’s Met Office, which has been recording temperature data since 1850, the next 10 hottest years after 1998 were, in order, 2005, 2003, 2002, 2004, 2006, 2007, 2001, 1997, 2008, and 1995.

When the temperature shifts this rapidly, living things may not be able to keep up. For instance, many insects, birds, and mammals time their breeding and migration based on temperature, while the many species of plants that they eat time their growth according to the sunlight. When this synchronicity gets thrown off, animals arrive on the scene before their meal is ready, the plants don’t get their seeds propagated, and species start going extinct. Whether we like to admit it or not, humans are part of this ecosystem.

This has happened before. About 250 million years ago, 9 of 10 marine species and 7 out of 10 of terrestrial species suddenly went extinct in what paleontologists call “The Great Dying.” They don’t know exactly what caused this mass extinction, but in all major proposed scenarios – an asteroid impact, a giant volcanic eruption, and changes in the composition of ocean gases – it was the resulting shift in the earth’s climate that, by throwing ecosystems out of whack, ultimately did in these creatures. Indeed, climate changes played a major role in all of the mass extinctions in the planet’s history.

None of this is to suggest that global warming will wipe out humanity. Homo sapiens, while perhaps not always living up to its name, has proven itself to be a highly adaptable species so far. But if we continue to allow our atmosphere to rapidly destabilize, will we be able to provide enough food and water, much less a measure of prosperity, for most of the 8 or 9 billion people predicted to be living here by midcentury? Do we really want to find out?

Posted in Climate, Earth, Global Warming, Science | Tagged: , , , | Leave a Comment »

Earth Will Become Planet Without Ice Caps

Posted by jase on June 28, 2009

Rising sea levels will not extinguish humanity, but they will transform life on planet Earth as we know it according to Peter Ward professor of biology and earth sciences at the University of Washington. Here are his predictions in a new book, The Flooded Earth, which will be published this July.

By 2050: Sea levels will rise 0.5 to 1 meter. Well established coastal cities will battle the rising waters with dikes and levees; other cities will see their underground infrastructure impaired and face building collapse.

By 2300: The seas will rise 20 meters reshaping the world’s geography, forming new rivers and lakes as Antarctica’s ice melts. Massive icebergs will form in the southern hemisphere interrupting historic shipping lanes.

2500-3000: the sea will reach its maximum levels completely wiping out coastal cities and forcing massive human and animal migration. Greenland and Antarctica will be transformed into prime farmlands. Southern regions will face the spread of tropical diseases and the possibility of mass extinctions.

Image above: Red represents areas where temperatures have increased the most during the last 50 years, particularly in West Antarctica, while dark blue represents areas with a lesser degree of warming. Temperature changes are measured in degrees Celsius. Credit: NASA/GSFC Scientific Visualization Studio.

Further reading:

Is Global Warming Part of Earth’s Natural Cycle: MIT Team Says “Yes” -A Galaxy Insight

Global-Warming Tipping Point: 9 Degrees Temperature Increase Would Devastate Earth’s Population


Posted in Antarctica, Earth, Global Warming, Historic Events, Southern Hemisphere | Tagged: , , , , | Leave a Comment »