{"id":793,"date":"2014-12-08T07:00:58","date_gmt":"2014-12-08T14:00:58","guid":{"rendered":"https:\/\/blogs.ubc.ca\/maribo\/?p=793"},"modified":"2016-07-19T11:40:18","modified_gmt":"2016-07-19T18:40:18","slug":"corals-suggest-el-nino-may-become-more-frequent","status":"publish","type":"post","link":"https:\/\/blogs.ubc.ca\/maribo\/2014\/12\/08\/corals-suggest-el-nino-may-become-more-frequent\/","title":{"rendered":"Corals suggest El Ni\u00f1o may become more frequent"},"content":{"rendered":"

By Jessica Carilli<\/a>, Assistant Professor UMass Boston<\/em><\/p>\n

\"IMG_5126\"<\/a>

The author at work<\/p><\/div>\n

In a warming world, key ocean-atmosphere processes, like the El Ni\u00f1o \/ Southern Oscillation<\/a>, are expected to change. An important question is whether the frequency or nature of climate oscillations like El Ni\u00f1o will change in the future.<\/p>\n

During El Ni\u00f1o, trade winds that normally blow warm surface waters from east to west across the equatorial Pacific Ocean weaken. The extra-warm surface waters that normally pile up in the west, called the Warm Pool, slosh back towards the east, shutting off upwelling off South America and reducing fishery productivity there. Rainfall patterns also change, moving to the east over the central Pacific and causing droughts in the west. El Ni\u00f1o also has global knock-on effects, like higher rainfall in California and drought in Australia.<\/p>\n

In 2010, Simon Donner and I went to the Gilbert Islands, in the Republic of Kiribati<\/a>, to collect core samples from large coral heads with the intent to learn how climate and the local coral reefs had changed over the past century.<\/p>\n

Corals build their calcium carbonate skeletons from seawater, and in the process record changes in their environment \u2013 like water temperature and salinity \u2013 within the chemistry of their skeletons. Coral skeletons also have rings like trees, so assigning dates to the resulting skeletal environmental records is straightforward.<\/p>\n

\"Gilbert<\/a>

Butaritari is near the northern edge of the Gilbert group of Kiribati<\/p><\/div>\n

The Gilbert Islands sit near the eastern edge of the Warm Pool, and are particularly sensitive to a recently discovered variant of El Ni\u00f1o, called El Ni\u00f1o Modoki or central Pacific El Ni\u00f1o<\/a>. These events seem to be increasing in frequency, which makes this region particularly interesting.<\/p>\n

Along with a team of researchers in Australia, we reconstructed water temperature and salinity at Butaritari<\/a>, in the northern Gilbert Islands, from 1959-2010 and compared trends to other Pacific coral records. The gradient in water temperature from east to west across the Pacific is intrinsically linked to an atmospheric circulation cell called the Walker Circulation, comprised of the trade winds at the surface, rising warm air and rainfall in the west, and sinking, cool dry air in the east.<\/p>\n

The records from Butaritari indicate that waters there have not warmed as much as water farther east along the equator. This means the west-east water temperature gradient has weakened over the past half century, and that the Walker Circulation \u2013 which breaks down during El Ni\u00f1o events \u2013 is weakening.<\/p>\n

A weaker Walker Circulation in turn means that El Ni\u00f1o events will be more likely to occur. We could therefore be in for a future of increased El Ni\u00f1o events, which has consequences for fisheries, farming, and freshwater availability \u2013 not to mention increased likelihood of natural disasters like flooding and wildfire in some parts of the world.<\/p>\n

The original publication can be accessed here<\/a> or contact Jessica<\/a> for a PDF.<\/p>\n","protected":false},"excerpt":{"rendered":"

By Jessica Carilli, Assistant Professor UMass Boston In a warming world, key ocean-atmosphere processes, like the El Ni\u00f1o \/ Southern Oscillation, are expected to change. An important question is whether the frequency or nature of climate oscillations like El Ni\u00f1o … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":28383,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1208,673],"tags":[],"class_list":["post-793","post","type-post","status-publish","format-standard","hentry","category-features","category-science"],"_links":{"self":[{"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/posts\/793","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/users\/28383"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/comments?post=793"}],"version-history":[{"count":2,"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/posts\/793\/revisions"}],"predecessor-version":[{"id":798,"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/posts\/793\/revisions\/798"}],"wp:attachment":[{"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/media?parent=793"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/categories?post=793"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/maribo\/wp-json\/wp\/v2\/tags?post=793"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}