Questions and Answers

1. What is global warming?

Global warming is the name for increase of the average temperature of the Earth atmosphere and the ocean, especially in the 20^th and 21^st centuries. There is no scientific consensus on the causes and the ultimate consequences of global warming.

The most common is the theory according to which global warming is a consequence of carbon dioxide and methane originating from industrial plants in developed countries. According to the theory, increased concentration of these gases leads to the so-called greenhouse effect in the atmosphere. Under the pressure of the movement for environmental protection, many governments have accepted the theory and signed the Kyoto Protocol, whose goal is the reduction of these gases emissions.

2. What is the greenhouse effect?

Greenhouse effect is a term for the heating of the planet Earth, created by disorder of energy balance between the amounts of radiation that earth surface receives from the sun and radiates towards space. This effect is the result of increase of the amount of radiation that can not be emitted in the universe as Earth surface prevents it, and the atmosphere absorbs it and becomes warmer. Earth's atmosphere absorbs part (about 30%) of energy that Sun directly emits, while the rest (of smaller wave radiation length) fall on the ground and warms it, and the earth then emits infrared rays ( of smaller wave length) which, in normal circumstances, mainly go to space. However, if there are gases in the atmosphere that absorb such radiation, there will be an increase in atmospheric temperature. This happened to the Earth's atmosphere in the last century.

In short, the sun emits energy of different wave length, a large part of it reaches the Earth's surface, contributes to the creation and maintenance of life on the Earth, while another part of this radiation is then emitted in the universe, and nature is in balance. If something keeps a part of that radiation, the balance is being broken, and problems emerge. What keeps the radiation is known as greenhouse gases, and problems which occur are known as global warming.

The main gases with greenhouse effect in the atmosphere are: carbon dioxide (CO₂), aerated water (H₂O), nitrogen dioxide (N₂O), methane (CH₄) and ozone (O₃).

In addition to these, there are gases that reached the atmosphere due to human activities, such as some chlorine and bromine compounds.

The effect occurs in a similar way as in the hothouse, where the solar rays of the visible ultraviolet part of spectrum break through the glass and warm the soil under the glass. The ground then emits infrared radiation which can not pass through the glass, so it remains inside and the soil remains heated. Thus, it is much warmer inside the greenhouses than outside of them. The planet Earth behaves in the same way if there is a substance that will act as a glass roof. When released from the factory chimneys and car exhausts, carbon (IV)-oxide (also known as carbon dioxide) and other harmful gases form a layer around the Earth that let the heat pass through the area but not return to space. In this way, the Earth surface becomes more and warmer each year.

3. What is the Kyoto Protocol?

From December 1 to 11, 1997, in the Japanese city of Kyoto, the leaders of 160 nations had meetings, to agree on the possible reduction of greenhouse gases in the atmosphere. On that occasion, the Kyoto Protocol was signed, under which the developed nations (which are the largest air polluters at the same time) committed to the overall reduction of emissions of CO₂ gas for 5.2 percent until the year 2012, which is a relative reduction comparing to the level of emissions in 1990. The reduction of emissions concerns only the 34 countries which together emit 13.7 million tons of carbon dioxide yearly, but in percentage amounts that correspond to their overall participation in the quantity. European Union, according to the Kyoto protocol, has an obligation to reduce emission by 8 percent, the United States 7, Japan by 6 percent, and other countries follow with smaller amounts.

4. What is carbon imprint?

Carbon print is the total amount of GAG emissions (Greenhouse gases - gases with greenhouse effect) produced directly or indirectly by the individual, organization, event or product.

Carbon print is a measure of our impact on the environment and climate change, and is expressed in tons (or kilograms) of carbon dioxide equivalents.

There are individual and national carbon imprint, but we can talk about carbon imprint of a household or organization.

Carbon imprint consists of two parts - the primary and secondary print:

• The primary imprint is the amount of direct GAG emissions that are released by fossil fuel combustion, including the energy we use in the household and the fuel we spend for personal transport (e.g. by car or plane). This is the print on which we can have a direct impact.
• The secondary imprint is the amount of indirect GHG emissions that are connected with the whole production and transportation cycle of all the products we use.

So, your carbon imprint is the sum of all emissions of carbon dioxide and its equivalents that that you cause by your activities in the certain period of time.

The most common time period for which the carbon print is calculated is one year.

5. How will climate change in Serbia?

In the region of South Europe, to which the Republic of Serbia belongs, beside the trend of temperature increase, further decrease of precipitation is expected as well, followed by the decrease of snowy days, soil humidity and availability of water resources.

With application of partial measures for reduction GHG emission, in the second half of this century, the average annual air temperature raising would be from 3 to 4^oC on the territory of Serbia.

6. Future consequences of climate change

• It is estimated that the water cubage accumulated in glaciers and snow cover would decrease, causing the reduction of water availability in the regions which are populated with more than 1/6 of the world population today.
• Capacities of many eco systems to naturally adapt to climate changes will be outdated within this century by the unseen combination of climate changes with incidents (such as floods, droughts, wildfires, insects, ocean acidity), and other factors of the global changes (such as changes in the soil exploitation, contamination…)
• On average, from 20 to 30 % of herbal and animal species will vanish from the face of the Earth if the temperature rises beyond 1.5-2.5^oC.
• With the temperature increase of more than 1.5-2.5^oC, and the correspondent increase of CO₂ concentration, huge changes are expected in the structure and functioning of the eco system, ecological interactions of species and geographical distribution of species, with prevailing negative consequences on bio diversity, or more precisely, on water supply and food provision.
• It is expected that the raising ocean acidity will have a negative effect on sea microorganisms, i.e. corals, and the species dependent on them.
• With the local average temperature increase of 1-3^oC, it is estimated that crop yield will rise in middle and high latitude, to drop later in some of the regions.
• In lower latitude, especially tropical regions with dry seasons, the decrease of crop yield is expected, even if the temperature grows less (1-2^oC), which can raise the risk from hunger.
• Globally, there would be the extension of potentials for food production within the limits of temperature increase of 1-3^oC, but beyond that, those potentials would be reduced.