WHAT IS GLOBAL WARMING? A speech in English class

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I delievered a 20-minute speech in our English class this Thursday. Though it was a really long speech, my classmates listened very carefully. After the speech, my English teacher asked them several questions to check whether they have learned anything it. Surprisingly, many of my classmates could repeat the framework and even content of my speech, which made me both moved and pleased. Some of my friends wanted me to send my powerpoint slide to them online because they got pretty interested in this topic and hoped to do some further study.Though I don’t think my research is comprehensive enough for the limited preparation time, helping classmates broaden their horizons and arosing their interest in this important topic was truly a satisfactory thing for me. The following is my speech and PPT slide.

GLOBAL WARMING

Good afternoon everyone. The 2021 Nobel Prize in physics amazed phycis lovers all over the world. It is the first time that Nobel Prize in physics was given to meteorology. You can see here that two of this year’s prize winners are meteorologists, which means who study the whether system and climate system. The Nobel committee’s decision seems can prove that climate change has become one of the severe issues affecting human society.

Today I would like to introduce you the main cause of climate change——global warming. I’m going to explain how global warming is formed, what crises it will lead to, and our solutions to this issue.

1. Cause of global warming

First let’s see how global warming is formed. For 2.5 million years the Earth’s climate has fluctuated, cycling from ice ages to warmer periods, but in the last century the planets’ temperature has risen unusually fast. Scientists believe it’s human activity that’s driving the temperatures up, a process known as ‘global warming’.

Ever since the industrial revolution began, factories, power plants and eventually cars have burned fossil fuels such as oil and pull, releasing huge amounts of carbon dioxide and other gases into the atmosphere.

These greenhouse gases trap heat near the earth through a naturally occurring process called the greenhouse effect, which means they trap some of the energy the earth radiates and reflect it back, warming the earth. Scientists now believe that the greenhouse effect is being intensified by the extra greenhouse gases that humans have released.

2. Crises caused by global warming


Some of you might ask, it’s normal for the temperature to have a slight change. We’ve experienced colder days and hotter days. A little bit of temperature rise seems won’t affect us that much.

However, that’s not the case. The speed of warming is unequal for different places on the earth, and among which the fastest ones are the polar areas. According to the polar amplification effect, if the earth’s temperature increase 2℃, then the temperature in polar areas will increase at least 10℃. You could see here the change of area covered by ice in north pole from 1975 to 2020.

As the ice melts, sea level rises, flooding coastal areas around the world. And we know that coastal areas are often important trade centers, for instance Shanghai and New York. What’s more, permafrost, which means frozen soil, will also melt and emit more carbon because there are methane(CH4) inside, which is another kind of greenhouse gases. Thirdly, as ice melts, the inhabitat for animals in polar areas is rapidly decreasing, and hence some species including the polar bear would face the danger of extinction.

We could see that all these three crises are caused by the rising temperature. However, does global warming only mean increasing temperature? Let’s see another example.

In February 2021, in the midst of rapidly warming global temperatures, an exceptionally severe cold wave hit large parts of North America, from Canada to Northern Mexico, leaving 10 million people without power. It was the coldest February In the U.S. in more than 30 years. Donald Trump posted a Twitter to complain about the cold wave and question the global warming. For example, he said:”windchill temperatures are reaching minus 60 degrees, the coldest ever recorded. What the hell is going on with Global Warming? Please come back fast, we need you!” He never believes in the existence of global warming, and he thinks ‘global warming’ and ‘extreme cold’ are totally unrelated things. However, that’s not the case.

In fact, it is the global warming that lead to this extreme cold. Actually, global warming will cause something called Unusual Planetary Wave Patterns, you can understand it as the distortion of climate system. And hence global warming will not only leads to extreme hot, it will also lead to extreme cold, extreme dry, extreme wet, etc. This theory is very complex and it’s hard to explain, but I will give you some examples to help you understand better.

We know that Brazil is in South America and there is a famous forest called Amazon rainforest. Rising temperatures resultes in less rainfall brought by the ocean currents, hence Brazil is getting drier and drier. Drought, high temperature, rainforest——what would happen? Forest fire. This is a picture of South America in 2019, the red point indicating there was a forestfire.

Circumstance in Australia is very similar. The four-month fire killed 3 billion animals and set Australia’s highest temperature on record for three days in a row.

Now let’s see the extreme cold in America. We mentioned that global warming can lead to disorders of the climate system, and among which one consequence is the spread of cold air over the Arctic. (This may be a little difficult to understand. You don’t need to understand why, it’s just a result.) What’s more, we know that there are mountains on the east and west sides of North America, and there is a plain in the middle, so the cold air from the Arctic does not spread on the west-east direction. As a result, cold air is concentrated in the center areas herr, leading to the extreme cold in the United States in February.

We’ve discussed about two kinds of crises that global warming may result in —— firstly, the rising temperature and its further consequences shows that global warming is part of climate change; secondly, global warming is also a cause of climate change as it leads to the distortion of climate system. Last but not least, I want to say that global warming is a cause of further global warming as well. As ice melts, rocks are exposed, which is easier to absorb heat. Permafrost melts, emitting methane(CH4), which is another greenhouse gas. AS global wildfire season extends, there are less trees and hence less carbon will be absorbed…… And all of these consequences will again intensify the global warming.

3. How to deal with global warming?

Finally, let us discuss how to deal with global warming and climate change. I don’t know whether you’ve ever followed the climate conferences, but at least for me, sometimes the climate conference is not like a meeting, it’s more of a quarreling. Every country has its own opinions. Last year, the United States even formally withdrew from the Paris Agreement. As global warming is such a severe issue, why it is so hard for countries to reach a consensus on solving it?

Nowadays an important way to deal with global warming is to limit carbon emissions. Carbon emission permits are given to each country according to their national circumstances. If the country doesn’t run use up all of their carbon permits, they can sell them to other countries; on the contrary, if a country’s carbon emission permit is not enough to use, then it has to buy from others.

In fact, developing countries, for example China and India, are currently the countries which emit the most carbon because of industrial production. On the other hand, developed countries have entered the post-industrial era with less carbon emissions, as they don’t need such large scale of industrial production and they have also developed some green technologies. For the developing countries, limiting carbon emissions actually means limiting development. But the developed countries won’t be restricted in this way. They can even sell permits unused to other countries and hence gain profit.

Thirdly, some island nations and a few coastal countries in Africa have a different idea: they are extreme environmentalists. They don’t have the need for industrial production, right? Some of them are in still in primary society or mainly depends on agricultural development. Hence they are also not afraid for the carbon emission limitation. However, these countries are close to the ocean and can easily be flooded once sea levels rise, so they are not satisfied with the current temperature target set by the United Nation(2℃) and are always requiring for a stricker target, 1.5℃ for example.

4. Summary

To summarize today’s speech, we have learned that it is human activity that caused global warming, and there are several crises that it may lead to. Firstly, global warming will directly result in rising temperature, which is part of climate change. Secondly, global warming is also a cause of climate change as it leads to the distortion of climate system. Lastly, global warming is a cause of further global warming as well. However, each country has its own idea on how to deal with this severe issue. Though fighting with global warming might be an arduous journey, I am still confident that us human-being have the wisdom and the ablility to save ourselves. That’s all of my speech, thank you for your patient listening.