Tropical nations to see above average sea-level rises

The melting of glaciers affects expected sea-level rise Copyright: Flickr/Doug88888

By: Claudia Mazzeo

We encourage you to republish this article online and in print, it’s free under our creative commons attribution license, but please follow some simple guidelines:

You have to credit our authors.
You have to credit SciDev.Net — where possible include our logo with a link back to the original article.
You can simply run the first few lines of the article and then add: “Read the full article on SciDev.Net” containing a link back to the original article.
If you want to also take images published in this story you will need to confirm with the original source if you're licensed to use them.
The easiest way to get the article on your site is to embed the code below.

For more information view our media page and republishing guidelines.

The full article is available here as HTML.

Press Ctrl-C to copy

<div class="article-wrap">
<div id="article-introduction">
<h1>Tropical nations to see above average sea-level rises</h1>
<h4>By: Claudia Mazzeo</h4>
</div>
<br />
<br />

<div id="article-body">
<p></p>
<p>[BUENOS AIRES] <span>Coastal areas in the tropics may see some of the largest sea-level rises due to take place this century because of <a href="http://www.scidev.net/en/climate-change-and-energy/climate-change-impacts/">climate change</a>, according to a study. </p>
<p>This would particularly affect the <a href="http://www.scidev.net/en/south-asia/">Indian Ocean</a> and <a href="http://www.scidev.net/en/south-east-asia/">Western Pacific</a>, which include many small island states, such as the Maldives, and vulnerable coastal deltas, including the Bay of Bengal. </p>
<p>The findings may help analyse the impacts of climate change and plan infrastructure for <a href="http://www.scidev.net/en/climate-change-and-energy/adaptation/">adaptation</a>, says the study, published in <em>Earth System Dynamics</em>.</span><span><br />
</span><span> </span></p>
<div style="margin: 0pt 10px 10px 0pt; background: #ededed; width: 50%; float: left;" class="box">
<div class="inherit_box box">
<h3 style="color: #ffffff; margin: 0px;">SPEED READ</h3>
</div>
<div>
<ul style="list-style: disc outside; margin: 10px 5px 10px 20px;">
<li style="padding: 0 0 5px;">Sea levels are predicted to rise up to 20 per cent more than average in tropical areas</li>
<li style="padding: 0 0 5px;">A combination of factors, including ocean temperature and ice melt are behind the difference</li>
<li style="padding: 0 0 5px;">But overall projections of the scale of sea-level rise remain uncertain</li>
</ul>
</div>
</div>
<p>At low latitudes, "this generally represent a 10-20 per cent higher sea-level rise compared with the global average and many vulnerable developing nations — especially small island states — are located in these areas," says lead author Mahé Perrette, a researcher at the Potsdam Institute for Climate Impact Research in Germany. </p>
<p>One reason for this above-average rise is that polar ice caps exert less gravitational pull on surrounding seas as they melt, causing water levels to fall, which, in turn, pushes up tropical seas. In addition, seawater expands as it warms, and different <a href="http://www.scidev.net/en/climate-change-and-energy/global-warming/">warming patterns</a> make it expand more in certain regions such as the tropics, than it does in others.</p>
<p>"The main conclusion we draw is that tropical regions are likely to experience relatively higher sea-level rise than polar zones due to the reduced gravitational pull of melting ice sheets located near the poles," Perrette says.</p>
<p>"Nevertheless, the bigger danger, which carries most uncertainties in the projections, is Greenland and Antarctica’s future contribution to sea-level rise [because of ice-sheet melting], with a range of about 0.5-1 metre by 2100 for a scenario leading to four degrees Celsius warming above pre-industrial temperatures," he adds. </p>
<p>Yet, actual sea-level rises in any one place can differ widely from the global mean because of changes in wind and ocean currents, and the gravitational adjustments that cause seawater redistribution away from ice masses, says Perrette. </p>
<p>"In Argentina, the melting of Patagonian glaciers and the Antarctic ice sheet [will] tend to produce lower-than-average sea-level rise south of about 40 degrees South. This means that in the region of Buenos Aires, which is further north, our projections indicate slightly above-average sea-level rise," he says. </p>
<p>Angel Menéndez, head of the Computational Hydraulics Program at the National Institute for Water in Argentina, says: "The uncertainties in the projections of sea-level rise due to climate change are relatively high". </p>
<p>He adds: "Depending on the assumed scenarios for ice-sheet melting, the global sea-level rise may vary from about 40 to 80 centimetres by the end of the century. However, local phenomena produce deviations from that global average." </p>
<p>Menéndez says that for Buenos Aires, the study indicates the sea level would only rise a few centimetres above the average global rise. "That is not necessarily good news, but at least one feels that we are not in the worst situation," he concludes. </p>
<p><span><a href="http://www.earth-syst-dynam.net/4/11/2013/esd-4-11-2013.pdf"><span>Link to full study</span></a></span></p>
<p> </p>
<p><!--[if gte mso 10]>

<![endif]--></p>

</div>
<div class="quick-links-wrapper">
<h3>You might also like</h3>
[related-articles]
</div>
<p>This article was originally published on <a href="https://www.scidev.net" target="_blank">SciDev.Net</a>. Read the <a href="https://www.scidev.net/global/news/tropical-nations-to-see-above-average-sea-level-rises-1/" target="_blank">original article</a>.</p>
<script type="text/javascript">
(function(e,t,n,r,i,s,o){e["GoogleAnalyticsObject"]=i;e[i]=e[i]||function(){(e[i].q=e[i].q||[]).push(arguments)},e[i].l=1*new Date;s=t.createElement(n),o=t.getElementsByTagName(n)[0];s.async=1;s.src=r;o.parentNode.insertBefore(s,o)})(window,document,"script","//www.google-analytics.com/ga.js","ga");var _gaq=_gaq||[];var _gaq=_gaq||[];_gaq.push(["_setAccount","UA-3223906-8"],["_trackEvent","article interaction","republished","https://www.scidev.net/global/news/tropical-nations-to-see-above-average-sea-level-rises-1/",null,true])
</script>
</div>

[BUENOS AIRES] Coastal areas in the tropics may see some of the largest sea-level rises due to take place this century because of climate change, according to a study.

This would particularly affect the Indian Ocean and Western Pacific, which include many small island states, such as the Maldives, and vulnerable coastal deltas, including the Bay of Bengal.

The findings may help analyse the impacts of climate change and plan infrastructure for adaptation, says the study, published in Earth System Dynamics.

SPEED READ

Sea levels are predicted to rise up to 20 per cent more than average in tropical areas
A combination of factors, including ocean temperature and ice melt are behind the difference
But overall projections of the scale of sea-level rise remain uncertain

At low latitudes, "this generally represent a 10-20 per cent higher sea-level rise compared with the global average and many vulnerable developing nations — especially small island states — are located in these areas," says lead author Mahé Perrette, a researcher at the Potsdam Institute for Climate Impact Research in Germany.

One reason for this above-average rise is that polar ice caps exert less gravitational pull on surrounding seas as they melt, causing water levels to fall, which, in turn, pushes up tropical seas. In addition, seawater expands as it warms, and different warming patterns make it expand more in certain regions such as the tropics, than it does in others.

"The main conclusion we draw is that tropical regions are likely to experience relatively higher sea-level rise than polar zones due to the reduced gravitational pull of melting ice sheets located near the poles," Perrette says.

"Nevertheless, the bigger danger, which carries most uncertainties in the projections, is Greenland and Antarctica’s future contribution to sea-level rise [because of ice-sheet melting], with a range of about 0.5-1 metre by 2100 for a scenario leading to four degrees Celsius warming above pre-industrial temperatures," he adds.

Yet, actual sea-level rises in any one place can differ widely from the global mean because of changes in wind and ocean currents, and the gravitational adjustments that cause seawater redistribution away from ice masses, says Perrette.

"In Argentina, the melting of Patagonian glaciers and the Antarctic ice sheet [will] tend to produce lower-than-average sea-level rise south of about 40 degrees South. This means that in the region of Buenos Aires, which is further north, our projections indicate slightly above-average sea-level rise," he says.

Angel Menéndez, head of the Computational Hydraulics Program at the National Institute for Water in Argentina, says: "The uncertainties in the projections of sea-level rise due to climate change are relatively high".

He adds: "Depending on the assumed scenarios for ice-sheet melting, the global sea-level rise may vary from about 40 to 80 centimetres by the end of the century. However, local phenomena produce deviations from that global average."

Menéndez says that for Buenos Aires, the study indicates the sea level would only rise a few centimetres above the average global rise. "That is not necessarily good news, but at least one feels that we are not in the worst situation," he concludes.

Link to full study