Changing Climate

Global mean surface temperatures have increased 0.6-1.2°F since the late 19th century. The 20’” century’s 10 warmest years all occurred within the last 15 years. Of these, 1998 was the warmest year on record. The snow cover in the Northern Hemisphere and floating ice in the Arctic Ocean have decreased. Globally, sea level has risen 4-10 inches over the past century. Worldwide precipitation over land has increased by about one percent. The frequency of extreme rainfall events has increased throughout much of the United States. Increasing concentrations of greenhouse gases are likely to accelerate the rate of climate change. Scientists expect that the average global surface temperature could rise 1.6-6.3°F by 2100, with significant regional variation. Evaporation will increase as the climate warms, which will increase average global precipitation. Soil moisture is likely to decline in many regions, and intense rainstorms are likely to become more frequent. Sea level is likely to rise two feet along most of the U.S. coast. Calculations of climate change for specific areas are much less reliable than global ones, and it is unclear whether regional climate will become more variable.

Emissions

Once, all climate changes occurred naturally. However, during the Industrial Revolution, we began altering our climate and environment through changing agricultural and industrial practices. Before the Industrial Revolution, human activity released very few gases into the atmosphere, but now through population growth, fossil fuel burning, and deforestation, we are affecting the mixture of gases in the atmosphere.

We track the gases that we release into the atmosphere in emission inventories. An emission inventory is an accounting of the amount of air pollutants discharged into the atmosphere. It is generally characterized by the following factors:

• the chemical or physical identity of the pollutants included,

• the geographic area covered,

• the institutional entities covered,

• the time period over which emissions are estimated,

• the types of activities that cause emissions.

Emission inventories are developed for a variety of purposes. Inventories of natural and anthropogenic emissions are used by scientists as inputs to air quality models, by policy makers to develop strategies and policies or track progress of standards, and by facilities and regulatory agencies to establish compliance records with allowable emission rates. A well constructed inventory should include enough documentation and other data to allow readers to understand the underlying assumptions and to reconstruct the calculations for each of the estimates included.

Impacts

Rising global temperatures are expected to raise sea level, and change precipitation and other local climate conditions. Changing regional climate could alter forests, crop yields, and water supplies. It could also threaten human health, and harm birds, fish, and many types of ecosystems. Deserts may expand into existing rangelands, and the character of some National Parks may be permanently altered. Unfortunately, many of the potentially most important impacts depend upon whether rainfall increases or decreases, which can not be reliably projected for specific areas.

By the year 2010 the increase in temperature would cause a rise in sea levels large enough to put the lives of up to 100 million people at risk. (This number will rise as the global population increases.) Flooding, as well as droughts in other areas, could spark off mass migrations as areas become uninhabitable. Tropical diseases would almost certainly spread northwards, causing “adverse impact on human health, with significant loss of life”.

For the first time in the scientific community, there is total agreement that the activity of human is at least partly responsible for the problem – specifically the emission of greenhouse gases like carbon dioxide, which is released by the burning of wood, coal and petroleum products. This is a significant departure from the position of many scientists who previously maintained that warming could be a result of natural climatic changes.

However, not all scientists are convinced that human-influenced warming actually affects the climate. Some maintain that higher temperatures, which increase evaporation and lead to heavier rainfall, might produce more clouds, which have a cooling effect. And, oceans might absorb most of the increased heat, leaving little to change the climate.

Reducing harmful emission is just one area in which the United Nations Intergovernmental Panel on Climate Change is decidedly optimistic. For one thing, in the short term it might not prove that difficult. Efficiency improvements alone could cut energy needs by as much as 30 per cent at virtually no extra cost. In the longer terms, harmful emissions will be reduced as the world changes over to cheaper, less environmentally damaging energy sources.

So, if it is economically and technically feasible to reduce harmful emission, why is almost nothing being done? There are two main reasons. The first stems from the uncertainty about how hot the planet is going to get.

Task 1

Interpret the following words and word combinations in English:

Chemical composition, heat-trapping property, wastes, byproducts, absorbent, photosynthesis, emission, strategy, standard.

Task 2

Answer the questions and give your own opinion.

1. What is the origin of Greenhouse effect?

2. What gases are responsible for global warming?

3. In what way do atmospheric greenhouse gases change the climate?

4. What could be the results of accelerating the rate of climate change?

5. What should be done to slow the process?

6. Are you an optimist? Do you believe that scientists find the way out of this dangerous situation?

Task 3

Render the text into English