Arts

'An Inconvenient Truth' that we conveniently forget

by Indeewara Thilakarathne

A private screening of the Academy Award-wining documentary film 'An Inconvenient Truth 'which explores the looming catastrophe of global warming was recently held at the Goethe Institute in Colombo.

The film directed by Davis Guggenheim and presented by former United States Vice President Al Gore, was in the form of a lecture on global warming and its devastating repercussions on humanity.

The film dwells on the facts and figures of unbridled industrialization, burning of fossil fuels and the primitive technologies that are still being used in some industries such as coal mining. These have substantially contributed to global warming, resulting in the melting of glaciers which inturn raise the sea level and endanger lives of animals such as polar bears and seals whose original habitat is disturbed.

Although some skeptics do not believe in the rationale behind 'An Inconvenient Truth', the film is based on hard facts and predictions regarding climate changes intermingling with personal events of the life of Al Gore.

In the main presentation, (dubbed 'the slide show') that Al Gore has presented world wide covering the entire planet, he explores the allied issues laced with global warming ranging from scientific evidence, politics and economics of global warming and the consequences of it on humanity.

For example, if humanity fails to reduce present emission of greenhouse gases, within the next ten years some land masses including the area of twin towers will be under sea water as a result of the rising sea level.

He also warns of harsh climatic conditions which differ from torrential rains which in turn causes floods of unimaginable magnitude to prolonged droughts resulting in the drying up of sources of rivers such as snow-capped mountains like Kilimanjaro in Africa. It has now been established some of the rivers which fed thousands of farmland had already dried up before they flowed into the sea.

Some segments of the film addresses the critics of global warming who have termed it as a campaign based on unfounded scare which is insignificant and unproven. For instance, Al Gore points out that the risk of melting up of major ice sheets in Greenland or in the West Antarctica which could raise global sea level by approximately 20 feet (6m), flooding coastal areas and producing 100 million refugees.

As the melt water from Greenland is lower in salinity, the water could halt the Gulf Streams current, triggering a dramatic local cooling in Northern Europe.

The film explores annual temperature and CO2 levels for the past 600,000 years in Antarctic ice core samples in order to explain the global warming phenomenon. A resemblance to Hurricane Katrina is used for those familiar with the 30-ft to 45-ft (9 to 14m) waves that destroyed almost a million homes in coastal Mississippi, Louisiana, and Alabama.

The documentary ends with a positive note that action coupled with political will could reduce and mitigate the effects of global warming, by reducing emission of green house gases such as carbon dioxide and growing more plants and trees. Gore appeals to the viewers to learn how they can support the initiative.

Gore's book of the same title was published at the same time as the theatrical release of the documentary.

The book contains additional and detailed information and Gore's commentary on the issues presented in the documentary.

WHAT IS GLOBAL WARMING?

The natural mechanism which warms the surface of the earth by trapping solar heat in the atmosphere making the earth habitable with the help of Carbon Dioxide and other greenhouse gases.

However, it has been unprecedently increased over the past decades by burning fossil fuels such as coal, gas and oil and the clearing of forests, thereby increasing the emission of Carbon Dioxide and other green house gases.

The phenomenon was accepted by a vast majority of scientists as real and is already happening as a result of human activity based on the growing body of scientific evidence.

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Global temperature record

Two millennia of mean surface temperatures according to different reconstructions, each smoothed on a decadal scale. The unsmoothed, annual value for 2004 is also plotted for reference.

Global temperatures on both land and sea have increased by 0.75 øC (1.4 øF) relative to the period 1860-1900, according to the instrumental temperature record. This measured temperature increase is not significantly affected by the urban heat island.

Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 øC/decade against 0.13 øC/decade).[5] Temperatures in the lower troposphere have increased between 0.12 and 0.22 øC (0.22 and 0.4 øF) per decade since 1979, according to satellite temperature measurements. Temperature is believed to have been relatively stable over the one or two thousand years before 1850, with possibly regional fluctuations such as the Medieval Warm Period or the Little Ice Age.

Based on estimates by NASA's Goddard Institute for Space Studies, 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree. Estimates prepared by the World Meteorological Organization and the UK Climatic Research Unit concluded that 2005 was the second warmest year, behind 1998.

Anthropogenic emissions of other pollutants-notably sulphate aerosols-can exert a cooling effect by increasing the reflection of incoming sunlight. This partially accounts for the cooling seen in the temperature record in the middle of the twentieth century,[8] though the cooling may also be due in part to natural variability.

Attribution of recent climate change and scientific opinion on climate change

Carbon dioxide during the last 400,000 years and the rapid rise since the Industrial Revolution; changes in the Earth's orbit around the Sun, known as Milankovitch cycles, are believed to be the pacemaker of the 100,000 year ice age cycle.

The climate system varies through natural, internal processes and in response to variations in external "forcing" factors including solar activity, volcanic emissions, variations in the earth's orbit (orbital forcing) and greenhouse gases.

The detailed causes of the recent warming remain an active field of research, but the scientific consensus identifies increased levels of greenhouse gases due to human activity as the main influence. This attribution is clearest for the most recent 50 years, for which the most detailed data are available.

Adding carbon dioxide (CO2) or methane (CH4) to Earth's atmosphere, with no other changes, will make the planet's surface warmer. Greenhouse gases create a natural greenhouse effect without which temperatures on Earth would be an estimated 30 øC (54 øF) lower, so that Earth would be uninhabitable. It is therefore not correct to say that there is a debate between those who "believe in" and "oppose" the greenhouse effect as such. Rather, the debate concerns the net effect of the addition of greenhouse gases when allowing for positive or negative feedback.

Contrasting with the consensus view, other hypotheses have been proposed to explain all or most of the observed increase in global temperatures, including: the warming is within the range of natural variation; the warming is a consequence of coming out of a prior cool period, namely the Little Ice Age; and the warming is primarily a result of variances in solar radiation.

One example of an important feedback process is ice-albedo feedback. The increased CO2 in the atmosphere warms the Earth's surface and leads to melting of ice near the poles. As the ice melts, land or open water takes its place. Both land and open water are on average less reflective than ice, and thus absorb more solar radiation. This causes more warming, which in turn causes more melting, and this cycle continues.

Due to the thermal inertia of the Earth's oceans and slow responses of other indirect effects, the Earth's current climate is not in equilibrium with the forcing imposed by increased greenhouse gases. Climate commitment studies indicate that, even if greenhouse gases were stabilized at present day levels, a further warming of about 0.5 øC (0.9 øF) would still occur.

Recent increases in atmospheric CO2. The monthly CO2 measurements display small seasonal oscillations in an overall yearly uptrend; each year's maximum is reached during the northern hemisphere's late spring, and declines during the northern hemisphere growing season as plants remove some CO2 from the atmosphere.

Greenhouse effect

The greenhouse effect was discovered by Joseph Fourier in 1824 and was first investigated quantitatively by Svante Arrhenius in 1896. It is the process by which emission of infrared radiation by atmospheric gases warms a planet's surface. On Earth, the major natural greenhouse gases are water vapor, which causes about 36-70% of the greenhouse effect (not including clouds); carbon dioxide, which causes 9-26%; methane, which causes 4-9%, and ozone, which causes 3-7%.

The atmospheric concentrations of CO2 and methane (CH4) have increased by 31% and 149% respectively above pre-industrial levels since 1750. This is considerably higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from ice cores.

Courtesy Internet