—An asteroid collision would be a threat against which we have no defence. But the last big such asteroid collision was about sixty-six million years ago and killed the dinosaurs. A more immediate danger is runaway climate change. A rise in ocean temperature would melt the ice caps and cause the release of large amounts of carbon dioxide. Both effects could make our climate like that of Venus with a temperature of 250 degrees centigrade (482 degrees Fahrenheit).
What Causes Global Warming?
Certain gases in the atmosphere block heat from escaping. Long-lived gases that remain semi-permanently in the atmosphere and do not respond physically or chemically to changes in temperature are described as climate change.
- It is caused by increased concentrations of greenhouse gases in the atmosphere, mainly from human activities such as burning fossil fuels, deforestation and farming.
- The average temperature of the Earth is rising at nearly twice the rate it was 50 years ago.
- Current levels of the greenhouse gases carbon dioxide, methane, and nitrous oxide in our atmosphere are higher than at any point over the past 800,000 years
What Is Affected By Global Warming?
It is causing a set of changes to the Earth's climate, or long-term weather patterns, that varies from place to place.
In the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 11,700 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.
Thomas Fire, the worst of those that roiled the region that fall, grew 50,000 acres in one day, eventually burning 440 square miles and forcing the evacuations of more than 100,000 Californians
A week after it was sparked, it remained, in the ominous semi-clinical language of wildfires, merely “15% contained.” For a poetic approximation, it was not a bad estimate of how much of a handle we have on the forces of climate change that unleashed the Thomas Fire and the many other environmental calamities for which it was an apocalyptic harbinger. That is to say, hardly any.
The fires that broke out in the fall of 2017
produced, in headlines and on television and via text messages, an
astonished refrain of the adjectives “unthinkable,” “unprecedented,” and“unimaginable.”
That October, in Northern California, 172 fires broke out in just two days—devastation so cruel and sweeping that two different accounts were published in two different local newspapers of two different aging couples taking desperate cover in pools as the fires swallowed their homes. One couple survived, emerging after six excruciating hours to find their house transformed into an ash monument; in the other account, it was only the husband who emerged, his wife of fifty-five years having died in his arms.
As Americans traded horror stories in the aftermath of those fires, they could be forgiven for mixing up the stories, or being confused; that climate terror could be so general as to provide variations on such a theme had seemed, as recently as that September, impossible to believe.
Facts about Gases that contribute to the greenhouse effect:
1 | Carbon dioxide (CO2), greenhouse gas responsible for greatest amount of warming to date. It is released through natural processes such as respiration and volcano eruptions and through human activities, have increased atmospheric CO2 concentration by 47% since the Industrial Revolution began.
3 | On a molecule-for-molecule basis, methane is a far more active greenhouse gas than carbon dioxide Methane is a hydrocarbon gas produced both through natural sources and human activities is much less abundant in the atmosphere.
5 | Nitrous oxide is a powerful greenhouse gas produced by soil cultivation practices. Like other greenhouse gases, nitrous oxide also traps heat in the atmosphere, absorbs radiation where it can live for an average of 114 years, according to the EPA. One pound of N2O warms the atmosphere about 300 times the amount that one pound of carbon dioxide does over a 100 year timescale.
6 | Chlorofluorocarbons (CFCs) is a synthetic compounds entirely of industrial origin used in a number of applications, destroy the earth's protective ozone layer, which shields the earth from harmful ultraviolet (UV-B) rays generated from the sun.
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