The Dwindiling Biodiversity
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The Rich Bio Diversity Is Being Killed and are we the cause !!!
Between 10-50% of wellstudied higher taxonomic groups (mammals, birds, amphibians, conifers, and cycads) are currently threatened with extinction Changes in biodiversity due to human activities were more rapid in the past 50 years than at any time in human history, and the drivers of change that cause biodiversity loss and lead to changes in ecosystem services are either steady, show no evidence of declining over time, or are increasing in intensity Roughly 40% of forest area has been lost during the industrial era, and forests continue to be lost in many regions, although forest is now recovering in some temperate countries Over the past few hundred years, humans have increased species extinction rates by as much as 1,000 times background rates that were typical over Earth’s history With “medium confidence,” approximately 20-30 % of plant and animal species assessed are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5-2.5 Celsius over 1980-1999 levels
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The Alarming FactsSome 12% of bird species and 23% of mammals are currently threatened with extinction. In addition, 32% of amphibians are threatened with extinction, but information is more limited and this may be an underestimate As one of the most species rich communities on Earth, coral reefs are responsible for maintaining a vast storehouse of genetic and biological diversity. Roughly 20% of the world’s coral reefs have been destroyed and an additional 20% have been degraded By 2020, some countries in Africa could see yields from rain-fed agriculture be reduced by up to 50%, with agricultural production and access to food severely compromised as a result of climate change By 2030, developing countries are expected to need a further 120 million hectares to feed their people
These all are the facts retrieved from the "The Convention on Biological Diversity(2007)". It hints the damage that has already taken place. The magnitude of damage is huge. You can experience tha damage in your surroundings. Untimely rains, severe summers, harsh winters, unexpected torrential water down pours. The List is endless. |
Biodiversity?? Why Should I care?
The loss of genetic diversity threatens food security: only 14 animal species account for 90 % of all livestock production, and 30 crops dominate global agriculture, providing an estimated 90 % of the world’s calories.
Due to the presence of greenhouse gases, the atmosphere is behaving like a greenhouse. The atmosphere also transmits the incoming solar radiation but absorbs the vast majority of long wave radiation emitted upwards by the earth’s surface. The gases that absorb long wave radiation are called greenhouse gases. The processes that warm the atmosphere are often collectively referred to as the greenhouse effect
The primary GHGs of concern today are carbon dioxide (CO2),Chlorofluorocarbons (CFCs), methane (CH4),nitrous oxide (N2O) and ozone (O3). Some other gases such as nitric oxide (NO) and carbon monoxide (CO) easily react with GHGs and affect their concentration in the atmosphere. The effectiveness of any given GHG molecule will depend on the magnitude of the increase in its concentration, its life time in the atmosphere and the wavelength of radiation that it absorbs. The chlorofluorocarbons (CFCs) are highly effective. Ozone which absorbs ultra violet radiation in the stratosphere is very effective in absorbing terrestrial radiation when it is present in the lower troposphere. Another important point to be noted is that the more time the GHG molecule remains in the atmosphere, the longer it will take for earth’s atmospheric system to recover from any change brought about by the latter. The largest concentration of GHGs in the atmosphere is carbon dioxide. The emission of CO2 comes mainly from fossil fuel combustion (oil, gas and coal). Forests and oceans are the sinks for the carbon dioxide. Forests use CO2 in their growth. So, deforestation due to changes in land use, also increases the concentration of Co2. The time taken for atmospheric CO2 to adjust to changes in sources to sinks is 20-50 years. It is rising at about 0.5 per cent annually. Doubling of concentration of CO2 over pre-industrial level is used as an index for estimating the changes in climate in climatic models.
Chlorofluorocarbons (CFCs) are products of human activity. Ozone occurs in the stratosphere where ultra-violet rays convert oxygen into ozone. Thus, ultra violet rays do not reach the earth’s surface. The CFCs which drift into the stratosphere destroy the ozone. Large depletion of ozone occurs over Antarctica. The depletion of ozone concentration in the stratosphere is called the ozone hole. This allows the ultra violet rays to pass through the troposphere. International efforts have been initiated for reducing the emission of GHGs into the atmosphere. The most important one is the Kyoto protocol proclaimed in 1997. This protocol went into effect in 2005, ratified by 141 nations. Kyoto protocol bounds the 35 industrialised countries to reduce their emissions by the year 2012 to 5 per cent less than the levels prevalent in the year 1990. The increasing trend in the concentration of GHGs in the atmosphere may, in the long run, warm up the earth. Once the global warming sets in, it will be difficult to reverse it. The effect of global warming may not be uniform everywhere. Nevertheless, the adverse effect due to global warming will adversely affect the life supporting system. Rise in the sea level due to melting of glaciers and ice-caps and thermal expansion of the sea may inundate large parts of the coastal area and islands, leading to social problems. This is another cause for serious concern for the world community. Efforts have already been initiated to control the emission of GHGs and to arrest the trend towards global warming. Let us hope the world community responds to this challenge and adopts a lifestyle that leaves behind a livable world for the generations to come. One of the major concerns of the world today is global warming. Let us look at how much the planet has warmed up from the temperature records.
Temperature data are available from the middle of the 19th century mostly for western Europe. The reference period for this study is 1961-90. The temperature anomalies for the earlier and later periods are estimated from the average temperature for the period 1961-90. The annual average near-surface air temperature of the world is approximately 14°C. The time series show anomalies of annual near surface temperature over land from 1856-2000, relative to the period 1961-90 as normal for the globe. An increasing trend in temperature was discernible in the 20th century. The greatest warming of the 20th century was during the two periods, 1901-44 and 1977-99. Over each of these two periods, global temperatures rose by about 0.4°C. In between, there was a slight cooling, which was more marked in the Northern Hemisphere. The globally averaged annual mean temperature at the end of the 20th century was about 0.6°C above that recorded at the end of the 19th century. The seven warmest years during the 1856-2000 were recorded in the last decade.
The year 1998 was the warmest year, probably not only for the 20th century but also for the whole millennium.
