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Ch. 1 SCIENTIFIC PREDICTIONS & Global Warming HURRICANE Forecasts SEA LEVEL & The Seven Metre Surge Ch.2 GLOBAL WARMING and COOLING The Greenland Ice Cap The Vostok Ice Core Ch. 3 CARBON DiOXIDE & the Grenhouse Effect Ch. 4 CLIMATE CHANGE Fact or Fancy Ch. 5 GLOBAL DOOMSDAY Beyond CO² The Population Explosion Your Comments are Invited comment @globalwarming-eh.ca Ch. 1 SCIENTIFIC PREDICTIONS & Global Warming HURRICANE Forecasts SEA LEVEL & The Seven Metre Surge Ch.2 GLOBAL WARMING and COOLING The Greenland Ice Cap The Vostok Ice Core Ch. 3 CARBON DiOXIDE & the Grenhouse Effect Ch. 4 CLIMATE CHANGE Fact or Fancy Ch. 5 GLOBAL DOOMSDAY Beyond CO² The Population Explosion Your Comments are Invited comment @globalwarming-eh.ca |
Ch. 6 "...far as Human Eye Can See" o While we ponder the threats of future disaster from Global Warming, we might benefit from further examination of the past, and a telescopic view of the so-called terrestrial planets (those that are nearest the sun) offers valuable evidence to inform that study. o For a close-up view of the Earth’s future, we need only look at our sister planet, Mars. o There’s some interest now in the prospect of a manned expedition to Mars to extend the exploration of that planet, already carried out by robotic vehicles and satellites. That remote exploration has shown there once was water on Mars and has also confirmed that there are ice caps at the poles. Recently too, we’ve observed the shorelines of ancient oceans that obviously covered much of Mars in the past. Whether or not we ever send humans to Mars, there's little doubt that planet Earth will eventually come to the same end as that so-called red planet. o When we look at the boiling cloud-cover on Venus and the cold desolation of Mars, we might well be seeing what Earth once was (Venus) and what it ultimately will become (Mars). o It’s generally accepted that Mars, Earth, and Venus, along with all the other planets and debris in the solar system, came from the "Big Bang." So it follows that they’re all about the same age and were formed from the same stuff, at about the same searing temperature. It follows also that because they’re all suspended in the same frigid medium (space) all have been cooling down ever since. Laws of nature also suggest that because the three terrestrial planets are relatively close to each other, they will have progressed through similar phases of change while cooling; first from a gaseous condition to solid; then as the temperature falls further, through a phase where water can exist as liquid as well as vapour; then to the point where basic life forms can survive; and finally to a condition where human life can flourish. But the cooling time will differ for each planet due to certain immutable laws of nature. One law of cooling relates to size. Large objects cool more slowly than those that are smaller. Big things hold more heat to be dissipated, so it takes longer for inner heat in a large object to migrate to the surface and radiate into its environment. Planets are no exception to that rule. Mars is about half the diameter of Earth and about one eighth of the Earth’s mass. So, on its way to reach equilibrium with the absolute cold of space, Mars inevitably cooled down more quickly than Earth. At this time, its mean surface temperature is an inhospitable –23º C; (9º F) much colder than Earth’s average of about +10º C. (50º F) o A second factor in cooling time is simultaneous heat input. Even as planets lose heat, they also receive heat from the Sun, and for each planet, the amount of heat it receives is related to its distance from the sun, and to its size. Because Mars is about 50% further from the Sun than the Earth’s average distance, the Sun’s rays that reach Mars are more diffused. Specifically, the Sun’s rays reaching Mars are less intense than those that reach Earth, in inverse ratio to the square of Mars’ greater distance from the Sun. Thus, solar radiation that strikes the surface of Mars will deliver only about 44% of the heat delivered to any equal area on the Earth’s surface. And because the diameter of Mars is only about half that of Earth (6800 miles vs 12,800 miles) the face that Mars presents to the sun is just 28% as large as the comparable face presented by Earth. So the aggregate solar energy that impacts on Mars is less than 13% of the total that impacts on Earth. (.44 x .28 =12.3 %) o Venus, by comparison, which is close to the size of Earth (about 95% of the diameter and 82% of the mass) is, on average, 30% closer to the Sun than is the Earth. So the Sun’s rays striking Venus are about 80% more intense than those reaching Earth and contribute substantially to its surface temperature of 480ºC (896º F). o That input of solar energy partially counteracts the radiation of heat from Venus and retards its cooling. o Despite that slower rate of cooling however, Venus, which was originally gaseous, has already become solid beneath its acidic cloud-cover, But it has a long way to go before it will be cool enough to host any familiar form of animal or vegetable life; longer still before it will be able to accommodate human life; and far beyond that again, before it finally runs down to become a silent dead mass like Mars. In the meantime, Earth will no doubt reach its end long before Venus. The time involved in that decline may or may not be within the scope of scientific or mathematical calculation, but it is certainly far beyond normal human comprehension. Best estimates are that the Sun, now at a temperature of 6000ºC (10,800º F) will not burn out for at least 5 billion years. The death of the planets will naturally precede that, but will still take an unimaginable length of time. Against the backdrop of that inexorable process and the near-infinite time involved in the Earth’s march to oblivion, the human race will occupy this planet in relative terms for a very brief moment. Our tenancy here might be ended by a catastrophic disaster like the meteor impact that obliterated the dinosaurs, or Earth may simply decline to the point where it can no longer support human life. There is little we can do to prevent the impact from a meteor, but we can have some effect, positive or negative, on Earth's rate of decline. If we fail to control the size of the Earth’s population and thereby minimize the sum of our rapacious appetites, we will simply accelerate our march to doom; for the time to our ultimate end will inevitably be in inverse ratio to our numbers. "Global Warming," "Climate Change," "The New Climate," and "Climate Crisis," are merely diversions from the more pressing issue of the population explosion. Back to the Top Back to Home |