CLIMATE CHANGE PART II
In part one I covered the significant effects of volcanic activity on the climate of the earth. In this part I am going to give a very brief summary of the totally devastating effects of objects from outer space colliding with the earth. There have been so many of these, known as asteroids or meteors, that scientists are constantly finding evidence of them in new places. Most of them are small like the one that recently slammed into Russia and the effects are only felt in a local area but some of them in the past have been huge and changed the climate of the entire world so drastically that most living things were wiped out. Recovery from some of these has taken thousands of years.
There have been at least five major ice ages in the Earth’s past. Outside these ages, the Earth seems to have been ice-free even in high latitudes.
Rocks from the earliest well established ice age, called the Huronian, formed around 2.4 to 2.1 billion years ago during the early Proterozoic Eon and can be found 10–100 km north of the north shore of Lake Huron extending from near Sault Ste. Marie to Sudbury, northeast of Lake Huron, with giant layers of now-lithified till beds, dropstones, varves, outwash, and scoured basement rocks.
The next well-documented ice age, and probably the most severe of the last billion years, occurred from 850 to 630 million years ago (the Cryogenian period) and may have produced a Snowball Earth in which glacial ice sheets reached the equator, possibly being ended by the accumulation of greenhouse gases such as CO2 produced by volcanoes. “The presence of ice on the continents and pack ice on the oceans would inhibit both silicate weathering and photosynthesis, which are the two major sinks for CO2
The Andean-Saharan occurred from 460 to 420 million years ago, during the Late Ordovician and the Silurian period.
The evolution of land plants at the onset of the Devonian period caused a long term increase in planetary oxygen levels and reduction of CO2 levels, which resulted in the Karoo Ice Age. It is named after the glacial tills found in the Karoo region of South Africa, where evidence for this ice age was first clearly identified. There were extensive polar ice caps at intervals from 360 to 260 million years ago in South Africa during the Carboniferous and early Permian Periods. Correlatives are known from Argentina, also in the center of the ancient supercontinent Gondwanaland.
65 million years ago, an asteroid, the size of the Isle of Wight, slammed into the Yucatan peninsula in Mexico at 20 times the speed of a bullet causing earthquakes, landslides, tsunamis and wildfires. This was named the Chicxulub crater and is probably the largest impact crater on earth.
At about the same time a chain of volcanic eruptions in India at what is known as the Deccan Traps spewed smoke and ash into the atmosphere for years, adding to the devastating effects of the Chicxulub impact.
The destruction, 65 million years ago, was so great it left most of the world a wasteland, shrouded in dust, perpetually cold and virtually devoid of all life and vegetation.
The dinosaurs, which had ruled for 160 million years, were wiped out in a matter of days. Large marine reptiles, like the mosasaurs and the plesiosaurs, the flying reptiles known as pterosaurs, giant snail-like ammonites and many species of marine plankton, were also obliterated. Bird species also suffered losses but survived.
Some mammals survived, however, ultimately setting the stage for the rise of human beings.
The conclusion by a panel of 41 international scientists, that it was an asteroid that caused the disappearance of the dinosaurs, has come in a bid to end decades of speculation.
This is real and terrifying climate change. It is not speculation built on a few isolated areas of temperature change and it points out the futility and the fallacy of the idea that mankind is going to have any significant influence on the climate of the earth.