Mass extinction on the Earth have always been caused by Ice Ages. Life comes back as the Ice Age ends, temperatures rise, and ice melts back into oceans. Life literally basks in happiness as the Globe warms.
CO2 is a bit player in the climate on the Earth. It is the Sun that controls both, the weather and the climate. In fact CO2 concentration is highest in atmosphere during Ice Ages. And Ice Ages are mostly the doings of ocean floor volcanic activities.
Over at americanthinker.com, Viv Forbes has a great blog post detailing the mechanism of Ice Age:
““Climate” is formally the thirty year “average” of weather. Climate is what we expect, on average – weather is what we actually get.
It is true that atmospheric conditions (dust, smoke, smog, aerosols, aircraft contrails, clouds and trace gases) can affect Earth’s weather. But none of these minor atmospheric constituents can generate energy – they merely filter, reflect, transfer or redirect a portion of solar energy. The effects of any changes tend to be short-lived, or reversed as the atmosphere clears; or they often trigger negative feedbacks that largely offset the initial effect. In particular, carbon dioxide does not drive the weather. No weather forecaster notes what tomorrow’s level of CO2 is likely to be, and no farmer wonders what it will be next spring.
The sun is the short-term weather wizard. It clearly controls the changing temperatures of day and night, winter and summer; it energizes the atmosphere to give the power to storms and cyclones; together with the Moon it produces tides and gyres and their changing cycles drive weather cycles on Earth. Meteorologists, long-range forecasters who study solar and planetary phases, and many intelligent farmers are best placed to forecast weather. The carbon-centric model predictions have failed dismally, suggesting strongly that carbon dioxide does not control weather.
Does CO2 drive significant climate change?
Earth currently basks in a benign climate interval, an interglacial warm period punctuated by occasional “Little Ice Ages” and between long periodic species-destroying eras of ice. As recently as twelve thousand years ago, large parts of Earth’s surface were covered by ice sheets up to 3km thick. Many species of mega-fauna disappeared suddenly in this cataclysm.
Global warming has never been a threat to Earth’s inhabitants, even with temperatures several degrees above those of this modern warm era. The real danger to life on Earth is global cooling, and its big brother, Snow-ball Earth.
Studies of sunspots and other solar variables suggest that a “Little Ice Age” is probably caused by solar variations. If solar activity decreases, two things happen. Firstly, Earth’s surface cools because of the reduced solar radiation. Secondly, the sun’s magnetic shield also weakens, allowing more cosmic rays to strike the atmosphere, thus creating more nuclei for cloud generation. The extra cloud cover adds to the cooling trend by shading the surface and reflecting more solar radiation. Those who study solar cycles are already warning that Earth is facing the likely onset of a modern “Little Ice Age”. See: More on Ice Age Predictions and Why Humans Have Little to do with Climate Change.
Heading for a little Ice Age now?
Intuition tells us that all we need for a “Big Ice Age” is sustained cold on Earth’s surface. This would indeed strip most of the moisture out of the atmosphere as rain, hail and snow; freeze lakes and rivers; produce cold dry deserts; and create growing fringes of sea-ice in previously temperate latitudes. But cold alone will not create thick continents of ice from coast to coast. To create massive ice sheets, energy is needed to evaporate a huge volume of water from the oceans which is then condensed in the cold atmosphere and added to the growing ice sheets.
Some ice ages also start suddenly. Millions of mammoths and other mega-fauna were buried in hail which was so sudden and sustained that their un-decomposed carcasses are still being excavated from their icy tombs.
For large ice sheets to grow quickly on land two things are required – warm seas to evaporate billions of tons of water from the oceans, and a frigid atmosphere over land to quickly turn that moisture into continental rain, snow and ice. As cloud cover increases, and snow falls in increasing amounts, the white snowy surface reflects more solar energy back into space, maintaining the cold atmosphere despite the expulsion of large quantities of two “greenhouse” gases (water vapor and carbon dioxide) from the warm ocean into the atmosphere.
To plunge Earth suddenly into a sustained “Big Ice Age” thus requires huge amounts of energy to heat the seas while not warming the atmosphere – neither solar energy nor any greenhouse gas can do this. Geothermal energy from widespread undersea volcanism is the most likely agent.”(from the blog post.)
Read the full blog post here.