A Rise in Sea Levels May Be Cause for Alarm

Global warming has had the effect of doubling the rise in sea levels around the world. Scientists say attempts to stall it by controlling greenhouse gas emissions may be futile.

The main cause of this acceleration is the increase in greenhouse emissions and the burning of fossil fuels. Before the end of this century, oceans will have raised half a meter, backing up coastlines by several hundreds of meters.

Scientists at the New Jersey-based Rutgers University analyzed cores drilled along the eastern coast. They looked through 500 meters of sediments and by using dating techniques, were able to calculate where dry beaches were over a period of 100 million years.

The analysis observed that sea levels increased by 1 mm each year during the past 6,000 years. They were caused by the melting ice sheets of the last ice age. During the previous 150 years, observations from satellites and tide gauges show sea levels rising by 2mm a year.

Prof Kenneth Miller led the study and attributed the rise to the increased usage of fossil fuel and consequent increase in greenhouse gases.

By 2100, the oceans are expected to be 40cm higher. This may cause beach erosion. Houses may get destroyed as beaches move back. The rise in sea levels may also add destructive power to storms triggered by hurricanes.

The research was published in the Science journal. It is known that many countries including Britain have signed the Kyoto protocol aiming to cut greenhouse gas emissions.

Prof Miller said there is very miniscule chance of slowing down the rise caused by climate change. It seems not much can be done about it, even if the Kyoto protocol were to be followed strictly.

In other two studies, that were also published in the Science journal, German researchers analyzed climate data for the previous 650,000 years, and concluded that the most abundant greenhouse gas, which is carbon dioxide, is rising 250 times faster than what could be caused due to any natural process. The levels of carbon dioxide now hover at 370 parts per million which is 27% higher than any time of the period under study.

The researchers measured the levels of gases locked into ice cores drilled in Antarctica. The ice core locks air pockets that were part of the atmosphere nearly 1 million years ago.

These cores are a good record left about the planet's environmental history. By analyzing the greenhouse gases in 10 cm ice chunks, researchers are able to reconstruct atmospheric gases at any time between the present days and the time before the four ice ages.

Lead author Dr Stocker at the Bern University (Switzerland) said that one has to look only at the past 900 years to see a dramatic increase in levels of carbon dioxide.

Ed Brook is a climate scientist from Oregon State University and he said greenhouse gases like methane, nitrous oxide and carbon oxide have risen dramatically since the start of the industrial revolution. The rise is mainly because of human influence.

Source:

SFGate