From Wikipedia ==
The 1980 eruption of Mount St. Helens, a stratovolcano located in Washington, in the United States, was a major volcanic eruption. The eruption (which was a VEI 5 event) was the only significant one to occur in the contiguous 48 US states since the 1915 eruption of Lassen Peak in California. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the volcano that created a huge bulge and a fracture system on Mount St. Helens' north slope.
Prior to the eruption, USGS scientists convinced local authorities to close Mount St. Helens to the general public and to maintain the closure in spite of pressure to re-open it; their work saved thousands of lives. An earthquake at 8:32:17 a.m. PDT (UTC-7) on Sunday, May 18, 1980, caused the entire weakened north face to slide away, suddenly exposing the partly molten, gas- and steam-rich rock in the volcano to lower pressure. The rock responded by exploding a hot mix of lava and pulverized older rock toward Spirit Lake so fast that it overtook the avalanching north face.
An eruption column rose 80,000 feet (24,400 m) into the atmosphere and deposited ash in 11 U.S. states. At the same time, snow, ice and several entire glaciers on the volcano melted, forming a series of large lahars (volcanic mudslides) that reached as far as the Columbia River, nearly 50 miles (80 km) to the southwest. Less severe outbursts continued into the next day only to be followed by other large but not as destructive eruptions later in 1980.
Fifty-seven people (including innkeeper Harry R. Truman, photographer Reid Blackburn and geologist David A. Johnston) perished. Hundreds of square miles were reduced to wasteland causing over a billion U.S. dollars in damage ($2.74 billion in 2011 dollars), thousands of game animals killed, and Mount St. Helens was left with a crater on its north side. At the time of the eruption, the summit of the volcano was owned by the Burlington Northern Railroad, but afterward the land passed to the United States Forest Service. The area was later preserved, as it was, in the Mount St. Helens National Volcanic Monument.
About Geo-engineering - this term seems to mean any way to take carbon dioxide out of the air, or block some of the heat from the sun, as the forests and volcanos do, naturally. The book also speaks of seeding parts of the ocean with primarily iron to encourage plankton to grow, which is another natural air cleaner, and feeds the marine life, as well.
Quote from page 196 of Gwynne Dyer's book, Climate Wars:
Paul Crutzen is a Nobel Prize-winning atmospheric chemist who risked his entire reputation by suggesting, in the now famous article originally published in Climatic Change in 2006, that it might become desirable or even necessary to put sulpher dioxide into the atmosphere in order to raise the planet's albedo (ability to reflect sunlight) and thus avoid runaway climate change. In doing so, he quite deliberately re-opened the public debate on the taboo subject of geo-engineering.
Geo-engineering must not be discussed in front of the children, because if they know about it they will behave badly.
... Quote from an interview with James Hansen, Director, NASA Goddard Space Studies Center, with the Author (Gwynne Dyer) June 28, 2008....
The human burning of fossil fuels is geo-engineering. The suggestions that we encourage re-forestation and the use of bio-char and the storing of carbon in the soil -- they're bio-engineering, but they're of a fairly natural order, and they have multiple benefits, so nobody would object to those. There are other, more extreme geo-engineering things that we could do -- and I say we should of course do all the other things first -- but you may get to a point where you see the ice-sheets are on the verge of collapsing. Then you have to consider these other possibilities.
I think the one that Paul Crutzen and others suggested -- putting sulphur dioxide into the stratosphere so it forms sulphuric acid droplets, a human-made volcano, in effect -- is an interesting idea. You might say that's dangerous, because we don't know what's going to happen, and to some extent that's true even for Crutzen's suggestion, but nature has performed that experiment. The Mount Pinatubo eruption in 1991 is interesting because it was large enough that for one year -- that one year after the eruption -- it was reflecting back to space about four watts of energy per square metre.
That's cancelling out the equivalent of doubled carbon dioxide, the equivalent of 560 parts per million of carbon dioxide. It's a big negative forcing.
One interesting point about it is that if you look at the melting in Greenland for the period when we have data, which began with satellite measurements in 1978 - 79, until the present, so thirty years, the year with the least melting was 1992, when those aerosols had maximum optical thickness. The sunlight has to go through them at a slant angle to hit this high-latitude ice-sheet, and it reflected enough sunlight away that it minimised the melting. So if the concern becomes especially these ice-sheets and their impact on sea-level, then you may have to seriously consider that. But frankly, it makes more sense to reduce the forcing that's causing the problem.
...end of quote.
Teach your children well....