Volcanoes actually cause global cooling. Same as sulfur-laden coal did up to and inlcuding the 1970's. When sulfur is spewed by coal plants or volcanoes, it ends up in the upper atmosphere as a sunlight reflector, as is the ash from volcanoes. Every time there's a massive volcanic eruption, the following summer is much cooler than normal. After Tambora in Indonesia erupted in 1815, some places in the US and northern Europe had no Summer at all. New England got snow in June!
As the EPA treehuggers made it more and more illegal to burn sulfur laden coal, thanks to it's acid rain and the burning of our lungs in smoggy cities, by the end of the 1970's sulfur laden coal burning was minimized, but the polar ice caps were maximized. Scientists were predicting the onset of the next ice age.
This is the ammo that right wing fanatics use to argue that the scientists don't know what they are talking about. But, when all facts are in, the left and the right obviously leave some facts out.
I haven't read about this ice-cap / sulfur-coal connection anywhere in literature. I've never read all that info together in one place, you have to look it up seperately. However, some left wing nut-jobs have started rumors that the "gubmit" is seeding the atmosphere with sulfur to cause global cooling and fight CO2 emissions. It's a well known fact that sulfur causes global cooling, and volcanoes do too.
It's a no-brainer to see the connection between 1970's regulations and global cooling. See this list of the seven "coolest" volcanic eruptions on record.
Since 1980 global temperatures have been on the rise, and glaciers and ice cpas have been shrinking at an alarming rate. Humans have increased CO2 in our atmosphere 38% since 1850. Unfortunately, we have removed the sulfur from our coal.
Why haven't volcanos caused global cooling since 1980? We have had plenty of eruptions. Mount Saint Helens erupted in 1980, with a volcanic explosivity index of 5 (vei 5), and it is estiamted to have caused 1 to 3 years of global cooling. The big island of Hawaii started erupting in 1983 and hasn't stopped. Mount Pinatubo in the Phillipines had a vei of 6 in 1991, and 2 to 5 years of global cooling.
Montserrat in the Caribbean erupted in 1995 sending an ash plume 6 miles high. Mount Etna in Sicily started erupting in 1998 and has erupted many times through December of 2006. How about the 20 mile high column of ash from Chaiten in Chile? That occurred in 2008, and we won't know all the global effects for some time. However, global temperatures keep going up.
|Mt. Etna vs. Sears Tower (now Willis tower)|
Mount Etna also erupted in 1971, during our little ice age of the 1970's. Mount Etna also erupted a lot in the 1600's and the 1700's during the so-called Little Ice Age, which itself lasted about 500 years, from 1350 to 1850.
Incidentally, there was a major volcanic eruption each year of the Little Ice Age, including Tambora and Laki, both with an estimated 2 to 5 years of gobal cooling, the most cooling of any eruption until Pinatubo in 1991. Even Krakatoa only had an estimated 1 to 3 years of cooling in 1883.
Some blame the Little Ice Age on the Sun's reduced output of 1/10th of 1%, due to a lack of sunspots from 1645 to 1715, a mere 70 years of the total 500 years. Hmmm... if a lack of sunspots causes global cooling, then we would be cooler half of each 11 year sun cycle.
Seems more logical that a volcanic eruption that lasts a few hours that causes a year without a Summer is a bigger factor than a measly drop of 1/10th of 1% of solar power.
Let's go back to the dawn of life on Earth for even more perspective. Startling facts from the History Channel, the Discovery Channel and Astronomy magazine about global temperatures should send a chill down your spine.
|Our Sun gets 10% hotter every billion years.|
It's a well known physics-fact the sun gets 10% hotter every billion years. Therefore the Sun was 35% cooler when life was known to exist on Earth 3.5 billion years ago. They calculate there's no way liquid water would be on Earth if the Sun were that cool. Therefore the 3.5 billion year old fossils were an impossibility.
However, the rock's mineral formations show that the atmosphere was mostly CO2 back then. We were a greenhouse like Venus is now. As the Sun warmed 10% each billion years, the Earth should have become hotter. However, blue-green algae evolved about 3 billion years ago, slowly reducing the CO2 levels, and making oxygen.
As the sun got hotter, the CO2 decreased. Global temperatures sometimes were very low. The Earth was a snowball from pole to pole three times in the past, when an ice age struck the entire planet. This occurred 2.2 billion, 710 million and 635 million years ago.
Multi-cellular life formed 1.2 billion years ago, but (I am guessing here) there was not enough oxygen for more complex life because Earth was not "terra-formed" yet. For example, there was so much iron in the oceans they were green. There are billions of years of rock sediments that are laden with iron-oxide from the oceans. The atmosphere had to wait for it's share of oxygen.
Oxygen was probably abundant by 540 million years ago when the Cambrian explosion occurred, and we got all sorts of creatures, like worms, mollusks, crustaceans, and all the different forms of ocean life before the age of the fishes. So it was only the last half billion years we went from microbes to humans.
In that time the Sun has warmed 5.4%. Global temperatures have kept in lock step with CO2 levels, according to ice cores going back 200,000 years. However, this website (http://www.geocraft.com/WVFossils/Carboniferous_climate.html) shows that global temperatures and CO2 levels were not closely related in the last half billion years.
Here's that website's graph comparing CO2 to glabal temperatures:
The far left of the graph is the Cambrian explosion 540 million years ago when complex life evolved.
It also shows that temperatures and CO2 levels are lower now than at any time in Earth's history, except one: the Carboniferous, aout 300 million years ago, before the time of the dinosaurs. During the Carboniferous we also had ice ages, thanks in part to the fact that all of Earth's land mass was at the south pole. This web site surmises that CO2 levels can surely go up without a problem. This site fails to mention that the sun is 3% hotter now.
Also, the web site mentions that after the Carboniferous time the supercontinent breaks up and moves north, the CO2 levels rise, the temepratures rise, and we see a period of desertification on the planet with major extinction events. (A major extinction event is what we are in now, by the way.)
This desertification era lasted until the middle of the Jurrasic when CO2 levels were 4.7 times higher than today and it was tropical from pole to pole. We don't want to go through the desertification stage, just to get to the nice tropical stage, do we? The desertification stage lasted about 70 million years!
The recent ice ages that we know so well have been within the last 2 to 4 million years. Besides speculation about the Milankovich cycles (precession of the Earth's axis, eccentricity of Earth's orbit, timing of apogee and perigee) causing global cooling, scientists say the ice ages were helped along when North America joined South America thanks to the Panamanian land bridge. This reduced the amount of heat moving to the North Pole thanks to the blockage of warm ocean currents that had been moving from the Pacific to the Atlantic, and on to the Arctic.
A lot of continental land mass had previously moved to the Arctic Circle, and obviously, to the south pole. This also aids ice ages, such as durng the Carboniferous period 300 million years ago. Becasue land freezes so easily in Winter, continental ice sheets are able to form.
Ice cores and sediments from the last 750,000 years tell us the Earth has 15 to 20 thousand years of warmth between 100 to 200 thousand years of glaciation. Therefore, we have about 2000 years before the next ice age. However, our future is HOT!
The sun will only get hotter, and in 1 billion years all water will be evaporated, and the Earth will be a hot, lifeless rock like Mercury. The Sun won't die for another 4 billion years after that. So, think about it. In Earth's 10 billion year history, complex life from worms to humans would only have evolved and survived for perhaps one billion of those ten. That's pathetic!
In the near term, the Earth will go through stages of flood, drought, desertification, ocean level rise, massive human migration, war and famine. Eventually the Earth may be tropical from pole to pole, as it was during the Jurrasic, when CO2 was particularly high. However, the Sun was 2% cooler then.
Does 2% more heat sound like a lot? Some scientists think that 1/10th of 1% is significant enough to cause the Little Ice Age. So, a 2% increase is 20 times more change than we had during the Little Ice Age. Couple that with the CO2 levels like the Jurrasic, and I say we are screwed.
We have already increased CO2 levels by 38% since 1850, the end of the Little Ice Age, and the beginning of the Industrial Revolution and massive coal burning. If we continue to increase CO2 levels, sure, we may go directly to tropical weather from pole to pole, like the Jurrasic. Doubtful. Evidence shows otherwise, as our planet is suffering desertification right now.
The next step beyond that is our demise thanks to the Sun being 2% warmer. We may only live a few hundred more years on Earth, not half a billion. That would be even more pathetic. We would be the shortest lived species on Earth, and will have caused the death of ALL species.