Belize

Disrupted Ecosystems VIII: Great Barrier Reef, Belize, 2006

Disrupted Ecosystems VIII: Great Barrier Reef, Belize, 2006

Belize Barrier Reef: photographed April 2006.

With respect to oceans and climate change there are principally four concerns:  1) ocean acidification; 2) changes in ocean currents, most notably the thermohaline circulation; 3) sea-level rise and 4) damage to ecosystems such as coral reefs.

The first two changes are of particularly grave concern, as they threaten to touch off feedbacks that could result in abrupt and catastrophic changes in the climate.  (There is good evidence in the climate record that such deadly, rapid changes have happened before).  Ocean acidification refers to changes in the ph balance of the ocean thought to be caused by the ocean’s absorption of carbon dioxide.  Current rate of acidification is the fastest in 65 million years, according to a recent study.  This could cause mass extinctions events and other major disturbances.  Ocean currents are one of the primary drivers of climate on the planet.  Any significant change to those currents (for example through ocean warming or introduction of sizeable cold water melt from icecaps) could likewise cause relatively sudden and drastic changes.  Much speculation exists about the possibility of altering or shutting off the thermohaline circulation, which accounts for our current distribution of heat and cold.  The impact of this happening would be to throw some northern latitudes into a deep freeze.  While there is little doubt that global warming will have some impact on currents, it is unknown how much and how fast.

Loss of ecosystems such as coral reefs due to ocean warming and other human impacts is yet another part of the story concerning climate change and the oceans.  It is worth remembering that the issue is not the loss of beauty but the broader impact that loss of such ecosystems has on the current balance of the earth.  Ocean research has been largely neglected in climate research, “despite its enormous importance in regulating global climate and its sensitivity to the impacts of climate change and ocean acidification,” according to the International Union for the Conservation of Nature, which published a recent report on oceans and climate change that is addressed to a general public (see first link above).

Disrupted Ecosystems X: Barrier Reef, Belize, 2006

Disrupted Ecosystems X: Barrier Reef, Belize, 2006

Costa Rica

Disrupted Ecosystems XXI: Monte Verde Cloud Forest, Costa Rica, 2006

Monteverde Reserve: photographed April 2006.

Per its vulnerability to the climate change, the following is from the IPCC: “The tropical cloud forests in mountainous regions will be threatened if temperatures increase by 1°C to 2°C during the next 50 years due to changes in the altitude of the cloud-base during the dry season, which would be rising by 2 m/yr.  In places with low elevation and isolated mountains, some plants will become locally extinct because the elevation range would not permit natural adaptation to temperature increase (FAO, 2002).  The change in temperature and cloud-base in these forests could have substantial effects on the diversity and composition of species.  For example, in the cloud forest of Monteverde Costa Rica, these changes are already happening.  Declines in the frequency of mist days have been strongly associated with a decrease in population of amphibians (20 of 50 species) and probably also bird and reptile populations (Pounds et al., 1999)” (IPCC, AR4 WGII, Chapter 13 p.596).  Note that the role climate in the extinction of the golden toad has been questioned by a 2010 study.

Per the impact that warming in the cloud forest may have on the climate by way of feedbacks:  Data gathered by Drs. Deborah and David Clark over the past 20 years in a Costa Rican rain forest indicates that rising temperatures are causing tropical forests to grow more slowly and if temperatures cross a certain yet unknown threshold, could start to decay.  (As temperatures rise, land plants release, rather than absorb, CO2 as their metabolism slows photosynthesis, which reduces their growth and increases respiration.)  This process could cause tropical forests to become sources of atmospheric CO2 rather than net reducers, significantly impacting the world’s climate.

Louisiana

Extreme Weather Events XV: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events XV: Plaquemines Parish, Louisiana, 2005

New Orleans: photographed November 2005.

“We are flying over Plaquemines Parish, which our hosts, the US Army Corps of Engineers, refer to as “Ground Zero.” A finger-like peninsula claimed from the marshes that follows the Mississippi River and extends 80 miles south of the Crescent City.  In most places it is no more than eight miles wide and everywhere is lower than the water.  Fifteen-foot levees hold back the Mississippi on one side and the marsh on the other.  The progression of town names tells a story:  Port Sulphur, Empire, Triumph, Venice, Tidewater.  The land gradually tapers off into the sea after a final flourish of oil refineries, tankers, helicopters and spider web of roads.

“Three months ago the 40-mile wide eye of Hurricane Katrina passed over this spit of land, raised the water some twenty feet above the levees and completely devastated every one of these towns.  From the helicopter the destruction seems systematic, even artful.  Trees felled by the surging water lie stacked in gentle waves across the peninsula; fields of debris drape the marshes and fold against the levees; plastic bags of every color make strange fruit in a desiccated orchard; cemetery-like rows of empty lots memorialize swept-away houses . . .

“. . . The destructive power of a hurricane’s winds is fed by energy latent in the warmth of ocean waters.  As water temperatures heat up, many believe storms will become more violent and more frequent.  To make matters worse, the more violent the storm, the more marshland gets shredded, and the water gets even closer.  Katrina destroyed 100 square miles of marshland outside of New Orleans, according to the US Geological Survey.  Most of it will not grow back.  Throw global-warming induced sea-level rise into the mix, which threatens to wipe out as much as 40 percent of the United States’ coastal wetlands before the end of the century, and it is easy to see why more half of the 800,000 people that fled the city have not returned as of November, according to recent Department of Labor statistics . . .”  (From a February 2006 article for the Spanish publication “Mu” by Sayler/Morris.)

Additional reference on the link between climate change and storm intensity and/or frequency can be found here and here.  It is remains one of the more debated and uncertain aspects of climate science.  Most scientists seem to agree the warming of the oceans will likely lead to an increase in the intensity of storms, but it is unsettled whether such warming will lead to more storms overall.

Extreme Weather Events IX: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events IX: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events IV: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events IV: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events X: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events X: Plaquemines Parish, Louisiana, 2005
Satsuma trees after the floodwaters subsided

Extreme Weather Events XIV: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events XIV: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events XII: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events XII: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events VII: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events VII: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events I: Plaquemines Parish, Louisiana, 2005

Extreme Weather Events I: Plaquemines Parish, Louisiana, 2005