Ecosystems of the world
Friday, 18 July 2014
Thursday, 10 July 2014
Green House Gases, Effect on Human Health, Climate Change
Green house gases
The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in a planet's atmosphere warm its lower atmosphere and surface. It was proposed by Joseph Fourier in 1824, discovered in 1860 by John Tyndall, was first investigated quantitatively by Svante Arrhenius in 1896, and was developed in the 1930s through 1960s by Guy Stewart Callendar.
The primary components of Earth’s atmosphere, N2 and O2 do not have absorption in the IR wavelength range, therefore, do not have a significant role in setting the surface temperature of the planet.
Greenhouse gas is efficient in absorbing IR light. The most important greenhouse gases are:
· H2O – Water vapor.
· Cabon dioxide – Carbon Dioxide.
· CH4 – Methane.
The most abundant greenhouse gas in Earth’s atmosphere is water vapor. Most of the greenhouse heating of Earth’s atmosphere is due to Water vapor absorption of IR radiation emitted by Earth, and then transferring the energy to the surrounding air molecule.
Carbon Dioxide
Cabon dioxide is a colorless gas:
• Condenses into solid form (dry ice) at -78°C in atmospheric pressure.
• Condenses into liquid at -57°C at pressure above 5.1 atmospheric pressure.
Atmospheric Cabon dioxide is derived from the sources for example:
• Volcanic out gassing
• burning of organic matter
• Respiration of living organisms
Cabon dioxide can be stored in the go under
• Highly soluble in water: forms H2CO3
• Dissolved Cabon dioxide in water can interact with silicate minerals to form carbonated minerals.
Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from Cabon dioxide, methane, tropospheric ozone, CFCs and NO. According to work published in 2007, the concentrations of Cabon dioxide and methane have increased by 36% and 148% respectively since 1750. These levels are much higher than at any time during the last 800,000 years, the period for which reliable data has been extracted from ice cores. Less direct geological evidence indicates that Cabon dioxide values higher than this were last seen about 20 million years ago. Fossel burning has produced about three-quarters of the increase in Cabon dioxide from human activity over the past 20 years. The rest of this increase is caused mostly by changes in land-use, particularly deforestration. Estimates of global Cabon dioxide emissions in 2011 from fossil fuel combustion, including cement production and gas flaring, were 34.8 billion tones, an increase of 54% above emissions in 1990. Coal burning was responsible for 43% of the total emissions, oil 34%, gas 18%, cement 4.9% and gas flaring 0.7% In May 2013, it was reported that readings for Cabon dioxide taken at the world's primary benchmark site in Mauna Loa surpassed 400 ppm. According to professor Brian Hoskins, this is likely the first time Caron dioxide levels have been this high for about 4.5 million years.
Effect on Human Health
November 1, 2011 Critics who doubt dire predictions about global warming question how much difference, say, a 2-degree temperature increase could mean to the planet.
According to Aaron Bernstein, quite a bit. Bernstein, a doctor at Children’s Hospital, instructor in pediatrics at Harvard Medical School, and Acting Associate Director of the medical school’s Center for Health and the Global Environment, was the first speaker in this year’s Environmental Health Colloquium Series, held on October 20, 2011 and sponsored by the Harvard School of Public Health’sDepartment of Environmental Health. An expert in how climate change and biodiversity loss can affect human health, Bernstein, MPH ’09, said that even a small global temperature increase could lead to troubling consequences, like rising sea levels, population displacement, disruption to the food supply, flooding, and an increase in infectious diseases.
While some don’t believe that greenhouse gases caused by humans are the main culprit behind global warming, Bernstein showed graphs indicating otherwise. The data, he explained, show pronounced increases in greenhouse gas levels in the United States during the Industrial Revolution of the late 1800s as well in the 1950s, when there was a postwar manufacturing boom.
Three consequences of climate change rising sea levels, rising temperatures, and increased precipitation stand to have the greatest impact on human health, Bernstein said. With rising sea levels, salt water can seep into into groundwater tables and taint the drinking water supply, and can also displace populations from low-lying areas. “And displaced populations have notoriously poor health statistics,” he said.
Heat waves another consequence of global warming can lead to thousands of heat-related deaths. Beyond that, there can be other troubling effects: decreases in crop yields, droughts, and dry conditions ripe for wildfires. Wildfires, in turn, lead to deforestation. Since trees absorb much of the excess carbon dioxide in the atmosphere, fewer trees mean higher levels of greenhouse gases in the atmosphere thus perpetuating the cycle in which warmer temperatures wreak atmospheric havoc.
Global warming can also cause abnormally heavy rains. A warmer atmosphere holds more moisture than a cooler one, Bernstein explained, but when it reaches capacity, the rain can be overwhelming. As an example, he cited the unprecedented spring flooding in the Midwest, which prompted the Army Corps of Engineers to intentionally breach the Birds Point levee in southeastern Missouri. The move saved the town of Cairo, Illinois, but it swamped 130,000 acres of Missouri farmland and 100 homes.
Key facts
· Climate change affects the social and environmental determinants of health clean air, safe drinking water, sufficient food and secure shelter.
· Global warming that has occurred since the 1970s caused over 140 000 excess deaths annually by the year 2004.
· The direct damage costs to health (i.e. excluding costs in health-determining sectors such as agriculture and water and sanitation), is estimated to be between US$ 2-4 billion/year by 2030.
· Many of the major killers such as diarrhoeal diseases, malnutrition, malaria and dengue are highly climate-sensitive and are expected to worsen as the climate changes.
· Areas with weak health infrastructure mostly in developing countries – will be the least able to cope without assistance to prepare and respond.
· Reducing emissions of greenhouse gases through better transport, food and energy-use choices can result in improved health.
Climate change
Over the last 50 years, human activities – particularly the burning of fossil fuels – have released sufficient quantities of carbon dioxide and other greenhouse gases to trap additional heat in the lower atmosphere and affect the global climate.
· In the last 100 years, the world has warmed by approximately 0.75 digree centigrade. Over the last 25 years, the rate of global warming has accelerated, at over 0.18 digree centigrade per decade1.
· Sea levels are rising, glaciers are melting and precipitation patterns are changing. Extreme weather events are becoming more intense and frequent.
What is the impact of climate change on health?
Although global warming may bring some localized benefits, such as fewer winter deaths in temperate climates and increased food production in certain areas, the overall health effects of a changing climate are likely to be overwhelmingly negative. Climate change affects social and environmental determinants of health clean air, safe drinking water, sufficient food and secure shelter.
Labels:
Gases
Wednesday, 25 June 2014
Global Warming, Its Effects, Matigation, Future Pridictions
Global warming
Means a clear and continuously increase in the World’s temperature due to boost in gases (greenhouse gases) and other pollutants. Because according to information from 1971, 90% of the warming occurred in the ocean. In spite the ocean play an important role in energy store. The word global warming is also used to submit to increases in normal temperature of the air and ocean .If we looking from the past the earth temperature rises from early 20th century and rises about 0.8 0C (1.50F). The temperature is rising consecutively in last three decades starting 1850.
According to scientific study the global warming has been increasing. In its fourth assessment (AR4 2007) of the relevant scientific literature, the intergovernmental panel on climate change (IPCC) accounted that most of the global warming was being caused due to increasing absorption of greenhouse gases produced due to anthropogenic activities. In 2013 according to IPCC affirmed that largest things that causes global warming is carbon dioxide (CO2) emissions on or after fossil fuel combustion, cement production, and land use alterations for instance deforestation.
Forth assessment report (AR4) by the intergovernmental panel on climate change (IPCC) has sum up a climate change model in 2007. They point out that during 21st century the temperature is likely to rise up to a more 1.1 °C to 2.9 °C (2.0 to 5.2 °F) for their lowest emission scenario and 2.4 to 6.4 °C (4.3 to 11.5 °F) for their highest.
Some external forcing can “force” the climate in the direction towards increase in temperature or decrease in temperature. Instances of external forces such as changes in atmospheric composition (e.g., increased attentions of greenhouse gases), solar luminosity, volcanic eruptions, and variation in earth,s orbit around the Sun. The 20th century Instrumental temperature record illustrates unexpected increase in global temperatures.
Greenhouse gases
It is the process in which absorption and emission of infrared radiation by gases in a planet's atmosphere warm its lower atmosphere and surface. This is proposed by Joseph fourier in 1824, discovered in 1860 by John Tyndall, was first investigated quantitatively by Svante Arrhenius in 1896, and was developed in the 1930s through 1960s by Guy stewart Callender.
Here are some greenhouse gases such as water vapours, which can cause about 35–69% of the greenhouse effect; cabon dioxide CO2, which causes 9–27%; methane (CH4), which causes 4–9%; and ozone (O3), which causes 3–7%. Clouds can also affect the radiation balance through cloud forcing like to greenhouse gases.
After the industrial revolution the amount of GHG, s increased in the atmosphere. The CO2, methane, and ozone increased in the troposphere leading to global warming. According to work published in 2007, the quantity of CO2 and methane have increased by 36% and 148% respectively since 1750.
Mitigation
The dropping of quantity in future climate change called mitigation of climate change. IPCC has describe mitigation as activities that decrease greenhouse gas (GHG) production, or increase the absorption ability of soil to absorb the carbon and other GHGs from the atmosphere. The researches and studies specify that the future reduction in emission of GHGs is important and we have to take serious action against the industries and we should apply carbon tax on them. We should use those resources which are renewable and which are less harmful for human, for the environment and for the biodiversity. Such as solar energy, wind energy and hydro energy etc. Climate mitigation also includes acts to enhance natural sinks, such as Afforestation.
If we want to improve the environment then we have adopt policies that will limit the greenhouse emission. But we have to think about our environment before the conditions become worse or irreplaceable. Energy-related carbon-dioxide (CO2) emissions in 2010 were the highest in history, breaking the prior record set in 2008.
Conclusion
The researches are studies indicate that the temperature of the earth is increasing because of natural and anthropogenic activities. If we don’t care about our earth then who will care? So the nature provides its services for us but us trying to deplete the services that are providing by nature. So we have to think and stop such activities which damage our earth or nature.
Labels:
Global
Sunday, 1 June 2014
Polar Climate - Characteristics, Current Status and Threats
Polar climate
The polar climatic regions are categorized on climate, temperature and radiation. Every year or every month polar climatic regions has average temperature of less than 10 degree centigrade. polar climatic regions like (Arctic and Antarctica) cover about 20% of the earth. In these regions sun shines 24 hours in the summer, and rarely ever shines at winter season.
Types of Polar Climate
There are two types of polar climate. The first one is ET, or tundra, the second one is EF, or ice cap climate. The tundra climate is characterized by having 0oC at least in one month. When tundra climate is arrived tress cannot grow, but some plants can grow which can have ability to grow in this climate. In ice climate, no plant can grow. This average is due to low radiation, albedo and high altitude.
Characteristics of Polar Climate
One of the most characteristic of polar climatic regions has large seasonal fluctuation on in coming solar radiation, little in winter and 24 hours sunlight in summer. As science already says that pole (north and south poles) receive less solar radiation, due to this the temperature is very cold, dry air at the surface.
Frozen Ice
The processes we discussed above will help in sustained very low temperature in winter. There are some places where temperature is below freezing point such as Antarctica Due to this low temperature water frozen through out the year. On the other hand Arctic and south ocean store large volumes of liquid water and there surface is covered with sea ice.
Sea Ice as Insulator
The Antarctic and Arctic region come in polar region. Due to polar climate the temperature in these regions is very low. So the sea ice in these regions work as insulator and insulates the underlying water from heat loss and due to less loss of heat, the organisms underlying the water survive. High albedo due sea ice and reflect back most of the solar radiation.
Climate Change
In Arctic and Antarctic It has been observed that the climate is changing during the past 2 millions years. These changing is well documented and predicted that if the temperature is rising in this manner then the ice will melt down. Due to this melting of ice the sea level rises and human life can be affected due to this like Tsunami is a good example.
Polar bears lives, give birth, and hunt on sea ice its means that polar bears depend on sea ice. They need it to travel from one region to another for hunting. The survival of cubs and mother depends on the climate and mother too. Less winter sea ice means that female polar bears have to go longer without food, which automatically impact on there health.
Variability in climate could threaten the life of polar bear and could affect the reproduction. Due to decline in Ice Sea certain seabirds like ivory gulls and little auks are also affected. There is another thing that some species of seal are vulnerable due to change in temperature and climate because the rarely come to ground like harp seal, spotted seal and the ringed seal.
Conclusion
Due to polar climate there are lots of water is store in solid form means sea ice and some species also depend on the polar climate for survival and for hunting.
Labels:
Climate
Subscribe to:
Posts (Atom)