Global Warming and the Sixth Mass Extinction
Global Warming and the Sixth Mass Extinction
What Is a Mass Extinction?
A mass extinction is a global era marked by a major reduction in bio-diversity. There have been five mass extinctions in the history of Earth. Each time, as many as 90% of the plant and animal species became extinct.
- The first mass extinction was the End Ordovician. It is known as the Ice Age.
- The next three were the End Devonian, the End Permian, and the End Triassic.
- The last was the Cretaceous—the one that killed off the dinosaurs and many other species.
What Are the Triggers for Mass Extinction?
One massive event can trigger a mass extinction, but it is often a series of events, such as volcanic eruptions or asteroid strikes. These cataclysmic events set up a chain reaction that cause the environment to change faster than ecosystems and organisms can adapt. The changes outpace evolution.
Global-warming was a factor in each of the last four extinctions. This should set off alarm bells. The warming of the earth is getting closer and closer to a tipping point.
Two Triggers of Mass Extinctions
Are Natural Cycles Causing Global Warming?
The Earth has been much warmer in the past and also much colder. The Earth’s overall climate is affected by many factors. Solar activity and variations in the orbit of the earth are the major factors. However, neither of these is causing the current warming crisis.
Global temperatures are influenced by sun-spots and solar flares which increase the amount of solar energy that reaches the Earth. A comparison of solar activity with temperatures on Earth over the past 1150 years shows a strong relationship between solar activity and temperature.
The sun has shown a slight cooling trend since 1960. Based on solar activity alone, we would expect a lower average temperature instead of the steadily increasing temperatures that we are actually observing.
The orbit of the Earth
The orbit of the Earth varies over millennia with respect to three major factors-- its eccentricity, its axial obliquity, and its precession. Taken together, these three factors are known as the Milankovitch cycles. Each of the three cycles can amplify or reduce the effect of the other cycles depending on their alignment.
Eccentricity: The Earth’s orbit is not perfectly circular; it is elliptical. The orbit varies from close to circular to more egg-shaped. These orbital variations are referred to as orbital eccentricity. This cycle occurs over 1000.000 years.
The point at which the Earth is closest to the sun is called perihelion, and the point furthest from the sun is called aphelion. The more elliptical the orbit is, the further the Earth is from the sun at aphelion. Currently, the Earth’s orbit is close to circular.
Axial obliquity: The angle of the Earth to the sun varies over the course of a year, and it is the reason we have seasons. But the degree of tilt varies—changing from greater to lesser over a 40,000 year cycle. This is referred to as axial obliquity and it affects the total amount of solar energy that reaches the Earth. Currently, the axial obliquity is at its midpoint and is decreasing
Precession: The precession of the Earth’s orbit is due to a wobble in its orbit. This cycle takes about 26,000 years. It changes whether the Northern hemisphere or the Southern hemisphere is closest to the sun at perihelion. This is important because land absorbs more heat than oceans, and the Northern hemisphere has more land mass. Currently perihelion occurs when it is winter in the Northern hemisphere and the Earth is tilted away from the sun.
At this time, the interaction of all the Milankovitch cycles predict a cooling trend. Instead we are seeing the fastest temperature increases ever observed.
The Milankovitch cycle matches the rise and fall of the Earth’s temperature over past eons—not perfectly, but very closely. In any event, the cycles occur very slowly, over thousands of years, much too slowly to be the cause of the changes we are currently seeing, even if all the cycles were aligned to produce “the perfect storm” of global warming.
It is apparent that human activity is counteracting solar factors that would otherwise be putting the Earth into a mini Ice Age.
Milankovitch Cycles and Their Effect on Climate Change
Is the Earth Experiencing Global Warming?
There can be no doubt that the earth is now undergoing global warming and the warming trend is accelerating. Most of the warming occurred in the past 35 years, with 16 of the 17 warmest years on record occurring since 2001. There were three record-breaking years in a row--2014, 2015, and 2016, with each year showing a higher average temperature than the year before it. 2017 may be another record breaker.
The oceans are also warming—surface waters as well as the waters at the bottom of the sea. The polar ice caps are shrinking every year. The sea levels are rising in part due to glacial melt and in part because water expand as it warms.
Is the Sixth Mass Extinction Already Happening?
The loss of bio-diversity is already evident.
In her book, The Sixth Mass Extinction: An Unnatural History, Pulitzer-prize winning author, Elizabeth Kolbert, documents the careful scientific research that shows how some plant and animal habitats are shifting year by year. Some organisms become extinct because they can exist only within a narrow temperature range and they are unable to migrate quickly enough so as to stay within that range.
The ecosystem of the sea is changing due to both warmer water temperatures and the greater acidity of the ocean waters. I recently watched a NetFlix documentary, Chasing Coral. I urge you to see it. It showed the devastating effect a rise of only one or two degrees in the average temperature of the water is having on coral. Half of the Great Barrier Reef corals have died off. The coral provide food and habitat for countless sea creatures. When these creatures are gone, larger fish will not have enough food to survive. The sea life that humans depend upon for food could be decimated.
The Sixth Mass Extinction
What Are the Effects of Global Warming for Humans?
Humans could lose much of the land mass they live on. Less ice means smaller ice-melts in the Spring and the loss of the water that some areas depend upon for agriculture and drinking. Changes in weather patterns are bringing more severe droughts and floods, dislocating many populations and disrupting agriculture. As previously mentioned, sea life, a vital part of the food chain, may be much diminished.
The changes caused by global warming will lead to massive migrations of people due to rising sea levels. Some low lying islands in the Pacific Ocean are already being evacuated—they will soon be submerged due to the rise in sea levels. There will be other migrations due to the loss of arable land and the resultant threat of starvation.
Increasingly violent storms are another threat. We know that higher sea temperatures produce more violent hurricanes. Storms and floods dubbed a once-in-a-thousand-years-storm or a once-in a-hundred-years-storm are happening every year.
- In 2017, the Northern hemisphere has been visited by three huge Category-5 storms in quick succession--Hurricane Harvey, Hurricane Irma, and Hurricane Maria.
- Hurricane Irma had wind speeds measured as high as 185 miles an hour and was 400 miles wide.
- I am beginning to fear that a new hurricane category will need to be added. We appear to be entering an era of Category-6 hurricanes.
The United States military has said that global warming could be the greatest threat to the security of the country. Massive migrations and a shortage of resources will lead to wars.
What Can We Do to Reduce Anthropogenic Warming?
Warming caused by human activity is called anthropogenic warming. Among climate scientists, 97% agree that the excessive warming of the planet is man-made.
We must stop the use of fossil fuels and the destruction of ecosystems on both land and sea. Renewable fuels can help forestall disaster. Fossil fuels are adding too much carbon dioxide to the air. This creates a “greenhouse effect” that holds heat within the atmosphere as well as “acid rain” due to too much carbon-dioxide dissolved in the water. It is not a coincidence that the steep rise in global warming began with the Industrial Revolution and has picked up with speed with the increased use of carbon based fuels.
There are two main institutions that can save the plant or destroy it based on their actions.
The role of religion
What role will religion play? I will take Christianity as the model because it is the one I know best. I expect the patterns observed in Christianity apply to other religions as well.
Some Christians want to reduce global warming.
- Some Christians believe in “Christian Stewardship” or “Christian Care.”They believe that God gave humans a mandate to protect His Creation. This group wants to halt global warming.
- Pope Francis supports the Paris Accord and he urged world leaders to heed the warnings of climate scientists. He said failure to do so will cause humanity to "go down." And in a not so thinly veiled reference to President Trump,he warned that "history will judge.
However, others clearly have other ideas.
- There are some who believe that God gave humans dominion over the planet, and they oppose all types of environmentalism. They feel entitled to exploit the resources of the Earth as they see fit. They believe that God will intervene to save humans.
- Some, like Pat Robinson, Chairman of the Christian Broadcasting Network, think hurricanes, and other natural disasters, are God's punishment for homosexuality and other sins.
- Finally, we have those who welcome the End-Times. They may even want to help things along.
We must hope that Christian Stewardship prevails.
The role of government
The strongest force to reduce carbon emissions is government. A total of 196 nations (every nation in the world except Syria, Nicaragua, and the United States) have signed what is called the Paris Accord, a pledge to reduce greenhouse gas emissions (Former President Obama spearheaded this agreement, but under President Trump, the United States has dropped out. However, some U.S. states have stepped up, pledging to meet the goals of the Paris Accord in their own state.)
With or without the Paris Accord, the United States must take steps to move to renewable fuels also known as "clean energy.". Funds must be allocated to subsidize companies who develop and provide wind and solar energy to encourage research and development. There should also be funding for training workers in the new skills needed, especially those workers who lose their jobs in the fossil fuel industry. Government might subsidize on-the-job training. In this way, the government can not only help reduce global warming, but also foster economic growth and national prosperity.
Two Sources of Clean Energy
What Is the Future for Life on Planet Earth?
It humans do not stop the behaviors that are leading to global warming, the changes will be like a snow-ball rolling down a snow covered mountain—getting larger and larger and faster and faster until it becomes an unstoppable deadly avalanche. Even if we went to zero emissions today, it would take decades to stop (and hopefully eventually reverse) the warming trend. Change will come slowly, but doing nothing is not an option.
The fifth mass extinction gave rise to conditions that favored the existence of small mammals. These mammals evolved and eventually gave rise to humans. Humans dominate the Earth today because of the fifth mass extinction.
The sixth mass extinction may be the end of humankind. The alarm bells are sounding. Will we listen?
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© 2017 Catherine Giordano