Climate changes. Fig. 2 The greenhouse effect

Vocabulary

Fig. 2 The greenhouse effect

The Earth has a natural temperature control system. Certain atmospheric gases are critical to this system and are known as greenhouse gases. On average, about one third of the solar radiation that hits the earth is reflected back to space. Of the remainder, some is absorbed by the atmosphere but most is absorbed by the land and oceans. The Earth's surface becomes warm and as a result emits infrared radiation. The greenhouse gases trap the infrared radiation, thus warming the atmosphere. Naturally occurring greenhouse gases include water vapour, carbon dioxide, ozone, methane and nitrous oxide, and together create a natural greenhouse effect. However, human activities are causing greenhouse gas levels in the atmosphere to increase. Greenhouse gases are mixed throughout in the atmosphere.

Predominant – преобладающий, доминирующий

Baseline – основание, базисная линия

fossil fuel combustion – сгорание твердого топлива

forestry sector – лесной массив, сектор лесного хозяйства

deforestation – вырубка леса

decomposition – разложение, распад, гниение

manure – удобрение, навоз

livestock – домашний скот

digestion process – процесс пищеварения

afforestation – засаживание лесом

Read the text and answer the following questions:

1. Comment on the diagram.

2. What are greenhouse gases caused by?

3. Talk about the main sources of emissions.

4. What is the role of human activity in producing emissions.

5. What do industry and agriculture emissions include?

6. Describe the processes presented at figure 2.

Since 1901, the Earth has warmed over 0.7°C. Warming in our future is heavily dependent on our actions in the short and mid-term. Even if emissions are capped at 2000 levels, an average temperature increase of 0.1°C per decade is already underway due to the time lag between the initial emitting of greenhouse gases, the subsequent changes in the atmosphere, and the continued self-amplifying processes which feed into other processes, called positive feedbacks.

Anthropogenic emissions are destabilizing the Earth's climate system. This is directly affecting air and ocean temperature, precipitation and extreme weather events, and creating positive feedbacks in the climate. For example, with more heat trapped in the atmosphere, global average air and ocean temperatures will rise, leading to a positive feedback in which one change results in another process altering the climate in a similar direction - further melting ice and snow both on land and at sea, raising the sea level, and causing other ecosystem changes. The complexity of the climate system also includes dampening, negative feedbacks. Another example, with warmer air temperatures, more water will evaporate and enter the atmosphere, resulting in more clouds. This in turn increases the atmospheric reflectivity, of the Earth and reduces the amount of solar radioactive energy absorbed.

This 0.1°C warming will thus occur regardless of our actions. A recent study found that the effects of climate change are largely irreversible, with impacts from carbon dioxide lasting more than 1,000 years. While current and future actions to reduce emissions will not deter the 0.1°C warming, they can prevent further warming. The threshold, or tipping point, of no return, in which the world is catapulted into catastrophic climate change, is generally understood based on science to occur at a 2°C increase over pre-industrial temperatures; however, as emissions continue rising, the world will pass other thresholds, triggering a domino effect of significant and adverse changes in the climate. Avoiding catastrophic climate change is an imperative, but changes even close to catastrophic do not bode well for the world either.

The number of cold days and cold nights in most of the world has a 90 per cent likelihood of decreasing while the number of hot days and hot nights are on the rise. Heat waves will make more regular appearances, as will heavy rainfall which can contribute to flooding. These changes will have asymmetric impacts on regions of the world based on each unique location and ecosystem. Countries further from the equator are expected to experience heavier precipitation, whereas tropical and sub-tropical regions are expected to receive less precipitation.

According to the Intergovernmental Panel on Climate Change (IPCC), an international scientific body established by the World Meterological Organization and UN Environment Programme and responsible for assessing climate change science through consensus, the world could warm by 1.8-4.0°C by 2100. As scientific understanding of the interaction between warming air temperatures and ice sheet melting improve, the possibility of sea level rise reaching one meter is increasing as well.

For reference, all countries with coasts will see changing coastlines of varying levels. Low-lying coastal countries, on the other hand, could witness flooding of large portions of their land. These areas are likely to be heavily populated. For example, one metre of sea level rise in Bangladesh translates into flooding of 14,000-30,000 km2, or 10-20 per cent of its total area, which would displace a fifth of the country's population. For many small island nations, one metre translates to near to total inundation, requiring complete population migration.

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