“When will the world be completely covered in water?”
Thank you for writing to me. Global warming is a controversial subject and highly complex. In fact, it is so complex that most adults do not understand it either. Even scientists, professors, and teachers have different opinions regarding global warming. Many people believe that global warming is a crisis that will someday destroy mankind. Some people do not even believe that global warming exists. After all, this year was one of the coldest winters in decades. And the hottest year on record was back in 1998, ten years ago. But I believe that the truth lies somewhere between these two extreme opinions.
You may have heard that there is a “consensus” among the scientific community that global warming is caused by increasing amounts of carbon dioxide(CO2) being released into our atmosphere by burning fossil fuels such as coal, oil and gasoline. CO2 is referred to as a “greenhouse gas.” Greenhouse gasses are an important part of our atmosphere. They form a protective “lid” on our planet that keeps the warmth from escaping into space. Without greenhouse gasses, the Earth would be too cold to support life as we know it. Though it is true that burning fossil fuels has caused a significant increase in carbon dioxide levels during the last 150 years, there is little or no evidence that this increase in CO2 has caused the Earth’s temperature to rise. Humans have been burning fossil fuels in significant amounts for about 150 years. CO2 levels in our atmosphere have been rising steadily during that same period. However, from the 1940’s through the 1970’s, the average temperature did not rise. It dropped. In fact, there is a relationship between CO2 and temperature, but it is different than what is described in the movie “An Inconvenient Truth.” By drilling deep into the polar ice caps, scientists can unlock samples of the Earth’s atmosphere that were trapped thousands of years ago. After examining these ancient samples of our air and comparing the data to global temperatures gathered from tree rings, coral reefs, and other fossil records, scientists have discovered that CO2 has historically not driven temperatures up. Quite the opposite is true. Rising temperatures occurred at many times over the last 650,000 years and each time CO2 levels rose 600-800 years AFTER the temperature increased. So it appears that the temperature goes up first, and the CO2 levels follow, not the other way around. Until recently, the reason for this was not understood. Some scientists now believe they may have found the answer. We know that the oceans on our planet absorb carbon dioxide from our atmosphere when the water is colder, and then release it back into the air when the water warms up. The Earth’s oceans are so large that it takes several hundred years for them to warm a few degrees. When they finally warm, they release CO2 back into the atmosphere. This is why some scientists believe that CO2 levels rise several hundred years after the temperature increases. One thing is certain, higher CO2 levels in the atmosphere have never caused the Earth’s temperature to rise in the past. However, that does not mean that CO2 levels will not affect temperatures in the future. More study is needed.
Besides carbon dioxide, there are other “greenhouse gasses.” Methane is a much more powerful greenhouse gas than CO2. Fortunately, there is much less of it in our atmosphere. But humans are also producing methane in large amounts, mostly by raising livestock such as cattle for food. But the most important greenhouse gas of all is water vapor. Water vapor is the most abundant greenhouse gas. It is responsible for the overwhelming majority of the “greenhouse effect” on Planet Earth. Humans have no affect on water vapor.
The Earth’s temperature is constantly rising and falling. There are many times during Earth’s history when the global temperature was warmer than it is today. There are many factors that occur in nature which cause the temperature to rise (and fall). The least of these is humans. Changes in the sun (solar cycles) affect the temperature on all the planets in our solar system, including Earth. Temperatures on Mars and the other planets have also been rising over the last several decades. Obviously, humans are not causing the temperatures on other planets to rise.
Cosmic rays from other solar systems in our galaxy affect the formation of clouds on planet Earth. These changes in cloud cover also affect the global temperature on the Earth. There are many other natural causes of climate change. The truth is that no one completely understands all the forces of nature that affect our climate. We are learning more about climate change every day, but we still have a lot to learn.
The Planet Is Fine
In your letter you asked “When will the world be completely covered in water?” The answer is NEVER. It’s true that the oceans are rising just as they have done many times in the past between ice ages. They rise 3 to 4 inches every century. This is a natural occurring cycle that been going on for millions of years. You may have seen pictures on TV or in movies of glaciers breaking apart and falling into the sea. This is also a natural process called glacier calving. This does not necessarily mean that the glacier is melting. Calving is what happens when a glacier grows so big that it can no longer support its own weight. It gets so heavy that portions of it break off and fall into the sea.
It is important to understand that even if all the ice in the Arctic Ocean melted tomorrow, the world’s oceans would not even rise one single inch. The reason for this is simple. When water freezes and becomes ice, it expands and takes up more room (volume). If you put a bottle of water your freezer, the bottle will break when the water freezes. When ice that is already in the ocean melts, the part that was above the surface only displaces the part that was frozen under the water so the water level doesn’t change. To demonstrate this, put an ice cube in a glass of water and fill it to the brim with water. When the ice cube melts, does the water in the glass overflow? The answer is no. Only the melting of land-based ice can cause the sea levels to rise.
Some scientists point to the Greenland Ice Sheet as evidence of global warming. The Greenland Ice sheet is different from the ice in the Arctic Ocean because it sits on top of land. Some scientists say that if the Greenland Ice Sheet melts, it will raise the Earth’s sea level by 20 feet. This is unlikely to happen any time soon, but there is evidence that Greenland was not always completely covered with ice. When the Vikings settled in Greenland, about a thousand years ago, the climate was much warmer than it is today. Though Greenland was not entirely green at the time, the southern part was very green in the late summer months and the average temperature was not as cold as it is today. A Viking named Erik The Red settled there and named it Greenland because he thought more people would interested in visiting there if it had an appealing name.
It is also important to understand that the ice at the South Pole is land-based ice. The ice that covers Antarctica is many times larger than the ice covering Greenland. But you might be surprised to learn that the Antarctic Ice Sheet is actually growing, not shrinking.
When I was in high school back in the 1970’s my science teacher brought in an article from Newsweek Magazine called “The Cooling World.” I have included a copy of it for you to read. Since the Earth had been going through a period of cooling for 30 years, some scientists believed that we were heading for another Ice Age. They feared that much of the land used to grow crops would be frozen and that many people would starve. Of course this turned out not to be true, but Newsweek sold a lot of magazines that week.
Remember the story of Chicken Little? As long as humans have been around, there have been people predicting the end of the world. Not one of them has ever been right. Obviously, we’re all still here so don’t worry, the planet is fine. I am including a great book for your project called “The Sky’s Not Falling” by Holly Fretwell. Please read it and share it with your parents, friends and teachers. It is the best global warming book available for children your age.
The Polar Bears Are NOT Dying
You may have been told that polar bears are in danger because of global warming. This is simply not true. Back in the 1960’s (when I was in the 6th grade) polar bears were in serious trouble. It was estimated that there were less than 5,000 polar bears left. Now there are over 25,000. That’s an increase of 500%!
You may have been told that polar bears are in danger because of global warming. This is simply not true. Back in the 1950’s polar bears were in serious trouble. It was estimated that there were less than 5,000 polar bears left. Now there are 25,000. That’s an increase of 500%!
The reason the polar bears are fine now is because humans stopped hunting them. It’s as simple as that. No matter how many pictures you see, no matter how many stories you hear, global warming is NOT killing the polar bears. When you see movies of polar bears swimming in the open ocean they are not drowning. They are excellent swimmers and have been documented to swim for 60 miles in open water.
Is Global Warming Our Fault?
In your letter you asked “How can we stop global warming?” That’s a great question. I’m not sure we can. We humans aren’t even sure that we’re causing it. Perhaps a better question would be “Should we even try to stop it?” Throughout man’s history, more people have been killed by cold climates than by warm climates. The climate is going to change no matter what we do. Sometimes it’s going to be warming, and sometimes it’s going to be cooling. I believe we should try to be as prepared for climate changes as best we can, whether the climate gets warmer, or colder. One undeniable (and inconvenient for some) truth is that even if we got rid of all the cars on the planet, we wouldn’t make a significant difference in the global temperature of Planet Earth.
You asked if air pollution is part of the problem. Air pollution is NOT part of the global warming problem. Pollution is a separate issue. They are two different things. No one wants to breathe dirty air. But carbon dioxide is not pollution; at least it wasn’t until a recent U.S. Supreme Court decision. Pollution from burning fossil fuels including carbon monoxide(CO), ozone, sulfur dioxide(SO2), nitrogen dioxide(NO2) and others are what make that icky yellow haze that we call smog. These gasses and particles are harmful to humans when we breathe them. But carbon dioxide(CO2) is an important natural part of our atmosphere. Just as we humans need oxygen(O2) to breath, plants need carbon dioxide. All green plants take in carbon dioxide and give off oxygen. No carbon dioxide, no plants. And since plants give us the oxygen that we humans need to breath, no plants no humans.
Solar, Wind, and other Renewal Energies
Solar Cars – “Why are they making them so expensive?” They answer to this one is simple. Where does the price of a solar car come from? Who decides how much the car will cost? The price of a solar car is determined by how much somebody is willing to pay for it (the buyer). Right now, solar cars and other alternative energy-powered cars are more expensive because less people want them. This is called “supply and demand.” If more people wanted to buy them, then more people would want to build them. As more companies begin to build them they will have to compete with other companies to get your business. This would eventually drive the cost of these new cars down until everyone can afford them. And it appears that this will happen soon. The price of oil is now at record levels, over $110.00 per barrel. When the price of oil and gasoline becomes too expensive, people will be forced to use different kinds of energy to power their cars and heat their homes. As more and more people become interested in solar and wind power, these technologies will continue to improve and become more efficient. We’re getting close, but we’re not quite there yet.
Once again, I would like to thank you for taking the time to write to me. I have never been asked to write to a 6th grader before. I hope this material finds you in time to complete your project and I hope you find it useful. I don’t have any posters to send you but I am including a sticker and the book “The Sky’s Not Falling” which I strongly recommend that you read. Please keep asking questions. Without questions there can be no answers. Good luck with your project.