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Climate A climate is the long-term average weather conditions characteristic to a certain area. Climate is divided into climate bands. Different climate bands evolve due to the position of the Sun and the Earth in relation to each other – sunlight falls under different angles to different regions of the Earth and warms them differently. In addition to that, a separation is made between macroclimate, mesoclimate and microclimate. Climate of a small territory is called a microclimate. A mesoclimate determines the conditions on a larger similar territory, and macroclimate on large territory of the Earth, in a geographical band, for example. Several elements of a natural environment have a different impact on the climate. For example, a lake influences a microclimate of an area that is not significantly larger than the area of the lake; mountain ranges already impact mesoclimate and the oceans – global climate. The Earth’s climate as a whole is determined by environmental elements on a global and cosmic scale. As climate research progressed, a connection between climate and environmental elements was found. On the basis of that, the concept of a climate system was formed. A climate system is the multilateral impact of an atmosphere, hydrosphere (ocean and inland water bodies), mainland (continents), cryosphere (snow- and ice areas) and the biosphere.
The most dynamic sphere of the climate system is atmosphere Atmosphere comprises mostly of nitrogen and oxygen, but also includes a very small percentage of the so-called other gases (i.e. water vapour, ozone, CO2, N2O, CH4, fluorinated gases etc) that come from both natural and anthropogenic sources. These chemically active gases are called greenhouse gases. The greenhouse gases capture long-waved heat radiation that reflects from the Earth’s surface back to the atmosphere – this phenomenon is called a greenhouse effect. In itself, there is nothing special in the greenhouse effect or the cyclic climate changes – the Earth’s climate is in constant change, in which the warmer and cooler periods change in cycles of about twenty or thirty thousand years. However, most scientists are convinced that one of the factors contributing to the climate change (growth of the greenhouse effect and rise in the average annual temperatures) is human activity, in the process of which more and more greenhouse gases are emitted into the atmosphere. This so-called anthropogenic greenhouse effect started to emerge only after the beginning of the industrial development in the 19th century and increased significantly in the fifties of the 20th century. The main anthropogenic influencers of the climate change are energy production, agriculture, waste management and industry, whereas the most important role is played by energy sector. The consequences of climate change can already be seen in Europe and worldwide, and these impacts are predicted to intensify in the coming decades. Temperatures are increasing, rainfall patterns are shifting, glaciers are melting, sea levels are getting higher and extreme weather resulting in hazards such as floods and droughts is becoming more common. But the climate changes do not influence only natural condition, but also our economy and society, and the choices on greenhouse gas reduction made today shall determine the weather conditions tomorrow.
International agreements The most important agreements that regulate the climate change on international level are the United Nations Framework Convention on Climate Change (UNFCCC) in 1992 and the Kyoto Protocol adopted in 1997 in Japan. As a member of the European Union (EU), Estonian opportunities and also obligations to actively participate in solving the global environmental problem – climate change– have significantly increased. The EU has developed an integrated climate and energy package (regulates the system of trading with the greenhouse gas emissions, the realm of renewable energy sources, CO2 emission limits for cars, fuel quality, carbon dioxide capture and storage (CCS), and the shared efforts to reduce greenhouse gas emissions). This package should enable for the EU to achieve its climate objectives by 2020: reduce greenhouse gases by 20 percent compared with 1990 levels, increase energy efficiency by 20 percent and ensure that 20 percent of the energy needs shall be met by renewable energy sources. In order to prevent dangerous interference with the climate system, the main climate protection objective on both international and the EU level is to keep the rise of the average global temperature as much below 2 degrees (Celsius) as possible, compared to the level before the Industrial Revolution.
Radiation We are surrounded by different kind of radiation: radio waves, microwaves, infra-red radiation, visible light, ultra-violet radiation and ionizing radiation. They are classified according to their wavelength. For human beings, the most dangerous radiation is ionizing radiation because its qualities are most hazardous to human tissue, causing diseases like cancer. Ionizing radiation may be natural. For example, radioactive gas from the ground – radon – emits alpha radiation. Radiography uses artificial x-rays to get pictures of the inside of people’s bodies.
Radiation protection People must be protected from excessive radiation. Principally a person can be subjected to radiation as many times as necessary and as rarely as possible.
According to the Radiation Act, radiation safety is organised by the Ministry of the Environment through the Environmental Board and the Environmental Inspectorate. This means that the Ministry of the Environment develops radiation safety policies and prepares legislative drafting, the Environmental Board issues radiation practice licences, conducts radiation monitoring and manages the emergency notification or early warning system. The Environmental Inspectorate monitors radiation practices. In order to ensure constant and systematic radiation safety, the national development plan for radiation protection for 2008–2017 was developed. |
