PRO/CON: The world's getting warmer, can nuclear power help us?

By Tribune News Service, adapted by Newsela staff
02.05.16

PRO: Using more nuclear energy will stop greenhouse gases

Nuclear power plants produce energy by splitting apart the nucleus, or center, of atoms. When the nucleus is split, heat is released. That newly released energy is then used to produce electricity. In turn, that electricity is sent through a grid to light our homes and power our computers. 

Nuclear power is only one of many ways of producing electricity. However, it is superior to any other method for one important reason. It is the best way to produce carbon-free electric power. 

Carbon is in carbon dioxide and other gases. It is released or emitted when fuels like coal, gas or oil are burned. People burn these fuels to power cars and all sorts of machinery. 

Carbon-containing gases are the main cause of the so-called greenhouse effect. Once they are released through the burning of fuels, they remain in the atmosphere and trap heat, just as heat is trapped in a greenhouse. Over time, this has caused average global temperatures to rise. 

A Valuable Tool

The global increase in average temperature is known as climate change or global warming. It is putting the planet at risk. Polar ice caps are starting to melt, thereby causing ocean levels to rise. Increasingly, coastlines and island nations are being submerged. In other parts of the world, droughts are becoming common as lakes and rivers dry up.

The world is starting to come together to try to limit climate change. Clearly, a carbon-free source of energy like nuclear power is a valuable tool in that effort.

Nuclear power now accounts for more than 60 percent of the United States' zero-carbon electricity. It is playing an essential part in the battle to reduce greenhouse gas emissions.

Wind power and solar power can also produce energy without releasing carbon. However, they are not constant. To work, the sun has to be out, or the wind has to be blowing.

Nuclear power plants run 24 hours a day, seven days a week. They are the only constant source of power that does not emit greenhouse gases.

An Excellent Safety Record

Many claim nuclear power is dangerous. Nuclear power plants produce radiation, which can be a dangerous form of energy. Even a small amount can cause severe damage to living things. Nuclear plants are built to keep radiation from leaking out, but many people worry such leaking will happen anyway.

Actually, there is no reason for concern. The nuclear power industry has an excellent safety record. 

The first commercial nuclear reactor began producing electricity more than 50 years ago. In all that time, there has not been a single death or injury from a radiation-related nuclear power plant accident in the United States. 

Many other countries also successfully rely on nuclear power. In France, nuclear power supplies 75 percent of the electricity, with enough to spare to provide almost a quarter of the electricity in Europe. 

The picture is very different in China, the world’s biggest carbon polluter. There, nuclear energy provides only 2 percent of the power. Coal remains China’s main energy source, and its use is increasing not only in China but throughout Asia.

Last month, representatives of most of the world's nations met in Paris, France, to discuss the climate crisis. The agreement they signed was far-reaching. It set a goal of bringing carbon emissions down to zero by the second half of this century.

Meeting that goal might seem impossible. However, France and Sweden show that countries can change their energy use very quickly. Both have been able to greatly increase their use of carbon-fee nuclear power in a relatively short time.

Reducing The Need For Oil

If the world built nuclear reactors at the same rate as France and Sweden have, the effect would be enormous. In 25 to 34 years, all the electricity now produced though burning coal and natural gas could be produced by nuclear power.

During this period, electric vehicles powered by nuclear-generated electricity could dramatically reduce the need for oil. These changes would greatly lower global carbon emissions and would help prevent dangerous climate change.

Meeting the new climate control goals is a daunting challenge. The world’s population is expected to increase to more than 9 billion by 2040. As a result, global demand for electricity will nearly double.

Unless the use of nuclear power is greatly increased, it will be impossible to both meet future energy demand and prevent dangerous climate change. Nuclear power is the only way to achieve both those goals at the same time.

CON: Nuclear power is only part of the answer, we need more solar and wind energy

The 2015 Paris climate agreement sets a remarkable goal. It calls on all countries to greatly reduce their greenhouse gas emissions.

Most of these emissions come from the burning of fossil fuels like coal, oil and natural gas. The message could not be clearer: We need to change the way we generate and use energy, and do so quickly.

The United States set itself a modest goal. It has pledged to cut emissions by around a quarter by 2025. The country has already taken some steps to meet that goal, but much more is needed.

Perhaps the most realistic approach is to increase the use of both nuclear power and renewable energy. Renewable energy sources, also called renewables, include such things as wind power and solar power.

A Better Bet

China has been using this approach. It plans to double its nuclear power capacity, and has 24 new plants now under construction. However, it is also expanding its use of wind and solar power.

Should the United States do the same? Yes, but only in part. Currently, our 99 nuclear reactors only account for about 8 percent of the electricity the U.S. consumes. Most of the energy we use, about 81 percent, comes from fossil fuels.

Nuclear power will have an important part to play, but it is unlikely to replace much fossil fuel use. It is still too expensive and too risky.

A better bet is to expand the use of renewables, while also working to make our energy use less wasteful.

Globally, nuclear electricity production has been leveling off while wind and solar power are soaring. There are good reasons for this.

One is cost. The new nuclear plants now being built in the U.S. are expected to cost $8 billion to $9 billion each, possibly more. It is also very expensive to safely shut down plants, which eventually becomes necessary when they are too old.

These very high costs make it difficult for the private utilities that provide our electricity to increase nuclear power generation. They see more promise and lower costs in natural gas-powered plants or in turning to renewables.

Nuclear Waste, And A Disaster

The problem of radioactive waste is another big reason to avoid an increase in nuclear power. There is currently no acceptable way to dispose of the highly radioactive waste nuclear plants create. 

There is also always the chance of the kind of disaster that occurred in Fukushima, Japan. In 2011, an earthquake there caused radiation-contaminated water to leak out of a nuclear plant, poisoning the surrounding area. The U.S. public remains understandably concerned that such a disaster could happen here.

A better way is for the country to greatly increase its use of renewables. At the same time, we should try to use energy in a way that is less wasteful. A non-wasteful use of energy is known as energy efficiency.

There are many ways to cut down on wasteful energy loss. Among them are improved building design, and a greater use of trains and buses in place of cars. We should modernize our electrical grid, and design better lighting, heating and cooling systems.

The United States also should put more money into research on promising new types of energy.

The federal government has long favored nuclear power and fossil fuels. For the past 10 years, renewables and energy efficiency have begun to receive significant support. We should keep moving in that direction, and quickly.

Questions:

1. What are the advantages of using nuclear plant?

2. What are the disadvantages of using nuclear plant?

3. Which countries are currently using nuclear plant as their main power supply?

4. Define "renewables" and give a few examples.

5. In your opinion, should our country use nuclear power and why?

After losing huge amount, Greenland ice is melting faster than ever

By Washington Post, adapted by Newsela staff

01.05.16

A new study has calculated just how much ice Greenland has lost since the year 1900. The number is astounding: 9,103 gigatons.

A gigaton is a billion metric tons.  For reference, the Statue of Liberty weighs about 200 metric tons.

The study was completed by 16 authors and was published in the magazine Nature. The lead author was Kristian K. Kjeldsen of the Natural History Museum of Denmark at the University of Copenhagen. 

Estimating the loss of ice was not easy. It required the use of several information sources. These included the distinct marks left by retreating glaciers on the landscape, extensive aerial photography from 1978 through 1987, and satellite and aircraft observations beginning in 1983.

All were merged to provide the new ice loss estimates. "It's the first observational-based study that shows where Greenland has lost its mass over the last 110 years," said Kurt H. Kjær, the paper's senior author.

How Greenland Affects Earth's Waters

The study offers a better understanding of how Greenland's ice loss has contributed to sea level rise. As the global temperature has gradually increased, ice in Greenland and throughout the Arctic has started to melt.  The melting ice has added to the volume of the oceans. Oceans all over the world have been affected, with water creeping higher onto the land. The study measures the effect Greenland's melting ice has had on sea levels.

It shows that the ice in Greenland is starting to melt more quickly. The amount of total ice loss doubled from 2003 to 2010 compared to ice loss throughout the 20th century (1900-1999). During this recent time period, an average of 186 gigatons of ice melted each year. Other estimates have put that number even higher. NASA currently states that Greenland is losing 287 billion tons of ice per year.

The study notes that ice melted in Greenland throughout the 20th century. The authors suggest that around 1900, the Earth started coming out of the Little Ice Age, a natural cool period. As the planet started warming, some ice began to melt. 

Humans And Global Warming

However, the speed of ice loss increased rapidly as major human-caused global warming kicked in. Most scientists believe that the release of greenhouse gasses, caused by human activities, has led to a dangerous increase in the Earth's temperature.

Since 1900, the research finds, Greenland's major mass loss has been coming quite consistently from a few key regions. Much of the melting has come from the northwest and southeast of the ice sheet, the vast layer of ice that covers about 80 percent of Greenland. Ice has also been melting from the Jakobshavn glacier in the southwest, Greenland's single fastest moving glacier. It is currently losing 25 to 35 gigatons of ice annually.

However, in recent years, the northeast of the ice sheet has started to melt as well. It features two major glaciers named Zachariae Isstrøm and Nioghalvfjerdsfjorden, which hold back 12 percent of all of Greenland's ice.

The new research suggests that the ice melting in Greenland has had a major effect on the rising sea level. The study estimates that 9,103 gigatons of ice have been lost from Greenland in the last 110 years. That would amount to a 2.5 centimeter of sea level rise. In other words, if the new study is correct, ice loss in Greenland has added an inch to the world's oceans.

The Inch Felt Round The World

An inch may not sound like much, but spread over the entire globe it is a staggering and dangerous amount of water. If Greenland's ice keeps melting, it could lead to disaster. If the Greenland ice sheet were to melt, it would lead to roughly 20 feet of sea level rise.

The study also measured the amount of fresh water that has traveled into the North Atlantic ocean from Greenland and elsewhere. According to Jason Box, a professor with the Geological Survey of Denmark and Greenland, most of that melted water has probably stayed in the North Atlantic.

This could interfere with the Atlantic Ocean's water currents and circulation, which are driven by differences in temperature and saltiness. Cold salty water sinks in the North Atlantic and travels southward. This pulls more warm water north. If too much fresh water is added to the North Atlantic, however, it could slow or eventually shut down the circulation. This would have dramatic effects on the Earth's climate.

Keeping The Melt Under Control

The fact that so much ice in Greenland has melted, contributing fresh water to the oceans, is troubling, and the melting appears to be speeding up. The key for the future of Greenland's ice comes down to global warming. The big question is how high global temperatures will rise and how long they will stay there. 

Last month, world leaders met in Paris, France, and agreed to the goal of keeping warming well below 2 degrees Celsius (about 3.5 degrees Fahrenheit). If achieved, that may be enough to prevent all of Greenland's ice from melting.

However, if the Earth gets much warmer than that, Greenland's ice will not last. "The ice sheets are doomed in a plus-3-Celsius world," says Box.

Questions:

1. How much ice has Greenland lost since the year 1900?

2. Who led this study?

3. How did they estimate the lost of ice?

4. What is the cause of the ice melting?

5. What causes global warming?

6. In your opinion, what are the steps that could be taken to resolve this problem?

Animals that were oceans apart are now together, due to melting Arctic ice

By Washington Post, adapted by Newsela staff

12.21.15

Animals have been showing up in strange places lately.

Gray whales live in the Pacific Ocean. In the spring of 2010, though, a single gray whale was spotted in the Mediterranean Sea. It was the first time a gray whale was seen in the North Atlantic in about 200 years. 

How Did YOU Get HERE?

Other animals that live in the Pacific have been appearing in the Atlantic as well. Likewise, creatures that live in the Atlantic Ocean have been seen in the Pacific. 

What is going on? A group of scientists, led by a scientist named Seabird McKeon, published a paper about the strange pattern. The paper was released on Nov. 30 in the magazine Global Biology. It said that the reason animals are moving between the Atlantic and the Pacific may have to do with climate change. 

Between the Atlantic and Pacific are giant continents. Sea creatures cannot cross them. Connecting the two oceans to the north is the Arctic Ocean. The Arctic is one of the coldest places on earth. Because of how cold it is, big parts of the Arctic Ocean are covered in ice. 

Melting Ice Makes Travel Easier

The ice usually keeps animals from using the Arctic to move between the Atlantic and Pacific oceans. Animals like whales and seals have difficulty getting through the ice. It gets in the way of their swimming and can block them from coming up to breathe. Birds can fly over the frozen ocean, but the ice prevents them from diving for fish.

These days, however, the ice is starting to melt. The climate is changing. Each year, the earth is getting a little warmer. As the Arctic has warmed, ice has started melting. As a result, passageways have opened up in the ice. 

McKeon and his team believe that this has allowed certain animals to cross through the Arctic, letting them move between the Atlantic and the Pacific. It is like a bridge has opened up between two oceans that used to be separate. Animals that used to always be apart can now mix. Scientists call this mixing "faunal exchange."

Studying "Faunal Exchange"

Many animals could become part of the faunal exchange. Birds such as Arctic terns, common eiders, Atlantic puffins and short-tailed shearwaters may start to move between the Atlantic and the Pacific. Beluga whales, ringed seals and Atlantic white-sided dolphins may do so as well.

No one can say for sure what effects the faunal exchange will have. To get some idea, though, McKeon and his team examined past examples of faunal exchange.

The Great American Biotic Interchange was a large faunal exchange. Several million years ago a thin strip of land called the Isthmus of Panama formed between North and South America. The new bridge allowed land animals to cross between the two continents for the first time. As a result, animals from North America invaded South America. They beat out many of the native animals there for food. 

Watch Out For Killer Whales!

McKeon and his team also looked at what happened when killer whales moved into Hudson Bay, a large body of water in Canada. As their name suggests, killer whales are hunters. All of the sudden, the animals in Hudson Bay had to be on the lookout for a new predator. Faunal exchange, in that case, altered the delicate balance of predators and prey.

McKeon and his team argue that the current exchange between the Pacific and Atlantic may have the same kinds of effects. It may lead to genetic changes as well. As animals move to new territories, they mix with different kinds of animals. Sometimes these new neighbors interbreed. New kinds of animals might be born as a result.

What Next?

At this point, scientists can only wait and see, and study. Most scientists seem to agree that faunal exchange between the Pacific and Atlantic is already occurring. It seems like it will only increase as more passages open up in the Arctic. The effects of faunal exchange, however, remain to be seen.

Questions:

1. Where do gray whales live in and where were they found in now?

2. Why the animals are moving between the Atlantic and the Pacific?

3. Why do animals cannot cross between the Atlantic and Pacific?

4. Why does the ice keeps animals from using the Arctic to move between the Atlantic and Pacific oceans?

5. What does "faunal exchange" mean?

6. What are the effects of current exchange between the Pacific and Atlantic?