Feeling hot, hot, hot: climate change and the Caribbean

Super hurricanes, higher temperature, and heavier rainfall—James Fuller looks at how global warming is threatening to redefine life in the Caribbean

Illustration by James HackettIllustration by James Hackett

Global climate change and its effects have moved from scientific theory to present-day fact, and the islands of the Caribbean, as well as its low-lying nations such as Belize and Guyana, are in the eye of the storm.

The larger developed and developing countries such as the US, China and India are largely responsible for, and hold the key to, stabilising climate change. But it is the smaller ones like the island states of the Caribbean that will pay the largest price if the situation doesn’t improve. Sea-level rise, “super” hurricanes, changing weather patterns, disrupted ecosystems, ocean acidification, coral loss and destruction of fisheries have been widely predicted.

Through overwhelming scientific evidence, and publicity such as Al Gore’s Academy- award winning film An Inconvenient Truth, the issue of global warming has been pushed to the top of the political agenda. But what exactly is it?

Global warming is the recorded increase of the average temperature of the planet’s near-surface air, and oceans, and its forecast continuation into the future.

The Intergovernmental Panel on Climate Change (IPCC) states that the earth’s air-surface temperature rose by 0.74 (± 0.18) degrees Celsius during the last 100 years and that it is set to increase another 1.1 to 6.4 degrees by 2100.

The IPCC further states that “most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”

Since the acceleration of the industrial age, from the mid-1800s onwards, man has pumped carbon dioxide and other heat-trapping gases into the atmosphere in unprecedented quantities.

These gases act like a blanket, trapping heat and warming the earth’s surface. There is now more carbon dioxide CO2 in the earth’s atmosphere than at any time in the last 650,000 years.

Seventy-five per cent of the increase can be attributed to the burning of fossil fuels, and a further 20 per cent to the cutting and burning of forests that trap carbon. The earth has not experienced such rapid temperature change in thousands of years.

So what does this mean for the Caribbean?

Estimates range as to both the extent and timescale of sea-level rise, but what is not in question is its potential impact on the Caribbean.

The Greenland Ice Field is two kilometres thick, and could lead to a seven-metre rise in sea level if it melts. The West Antarctic Ice Sheet could add a further five metres. These are already melting, with five per cent of the Greenland Ice Field gone and eight per cent of the West Antarctic Ice Sheet lost.

With large areas of the Caribbean, both island and mainland, lying just above sea level, increased flooding, storm surges and coastal breaches are expected in the coming years. If sea levels continue to rise, they will eventually overwhelm the coastal mangroves and wetlands which are nature’s protective barrier along vulnerable coastlines. As well as exposing other areas further inland, this would devastate the biodiversity of these important habitats.

With sea-level rise comes the problem of saltwater intrusion, which affects the agricultural productivity of coastal land as it becomes salt-saturated, as well as making fresh water scarcer for people who live in the area.

“We have installed a desalination plant on one of the islands off Belize, and one peninsula is having water piped to it from the mainland,” says Carlos Fuller, deputy director of the Caribbean Community Climate Change Centre (CCCCC). “This will become increasingly common.”

Half of the CO2 emitted into the atmosphere ends up in the ocean. That CO2, when mixed with water, produces carbonic acid, which in turn ties up the calcium that shellfish need to make their shells.

Professor James Gustave Speth, dean of the Yale School of Forestry and Environmental Studies, said: “Maintained at current rates, by the end of the century the oceans will become acidified to the extent that coral, plankton and shellfish life will be undermined.”

This would in turn affect fish stocks, affecting the livelihood of fishermen, whilst also limiting an important regional food supply.

Exceptionally warm sea water for long periods of time spells bad news for reef systems, as it causes coral bleaching and eventually death. Bleaching occurs when the stress of warmer water triggers the coral to expel the symbiotic unicellular algae (called zooxanthellae) that both nourishes and gives it colour. This exposes the white calcium carbonate skeletons of the coral colony.

While any one of a number of environmental stress factors can cause corals to bleach, high water temperatures have been the primary cause of recent coral bleaching observed around the world.

Sir Nicholas Stern, in his hugely influential 2006 publication, The Stern Review Report on the Economics of Climate Change, says a rise of one degree Celsius would bleach 80 per cent of coral reefs. In fact 20 per cent of coral reefs have already been lost, with a further 20 per cent under severe threat.

Dr Ulric Trotz, chief science adviser for the CCCCC, recently pointed out: “Warming of the Caribbean Sea is impacting on the coral reefs, which are an important resource for livelihoods both for fishing and tourism.”

Fuller explains that his homeland of Belize, which has over 200 miles of reef systems, has already been seriously affected. “Belize has had three serious coral-bleaching episodes in recent years, in 1995, 1998 and 2005.

“Fortunately, the waters cooled off enough for them to recover to some degree.”

But this may only be a stay of execution, if the oceans continue to heat up in the coming years.

A recent study done in French Guiana also warned of the potential impact on fishermen of warmer seas. It revealed that a one-degree rise in ocean temperature could mean highly-prized migratory ocean species, such as the dolphin fish, might leave their southern feeding grounds and head north to find cooler waters.

One of the most demonstrable impacts of increased ocean temperature is its effect on the intensity of hurricanes. Simply put, hurricanes feed off the warmth of the ocean surface, so the warmer the ocean, the more destructive the hurricane.

The impact of recent hurricanes such as Ivan, on Grenada in 2004, and Katrina, on New Orleans in 2005, is self-evident.

The IPCC has warned of more intense hurricanes and Climate Institute President John Toppin has said that a “business-as-usual energy policy by larger nations may, within this century” see several Caribbean nations succumbing to super-hurricanes.

“Hurricanes are also taking a more southerly track now,” adds Fuller, “so locations which were relatively safe historically, such as Trinidad, are now more vulnerable.”

It’s not all about the sea, either. The past three decades have seen a trend of increasing mean air temperature in the Caribbean. Predictive models suggest a further regional increase by 2080 of between one and five degrees Celsius, with greater warming being experienced in the north-west Caribbean (Jamaica, Cuba, Hispaniola, Belize) than in the east, according to the CCCCC.

This has an impact on animals whose life cycles are sensitive to changes in temperature. During 1999/2000 Belize experienced higher than normal heat and humidity, which triggered an explosion of the pine bark beetle population. As a consequence 75 per cent of the nation’s pine forests were wiped out.

There is also already evidence of an increase in the number of unpredictable weather events.

“We have had a number of heavy rainfall events recently, not related to hurricanes or tropical storms, which have wiped out bridges and damaged agriculture,” says Fuller. “In September we had 10 inches of rain in a single day. Belize City was under water. Guyana is experiencing this also.”

Even though freak weather incidents like this may be on the increase, projections from the CCCCC indicate that in terms of overall rainfall, the Caribbean basin will be a drier place by the 2080s.

The combination of the two factors is not good for farmers. Studies suggest that a 1–2 degree Celsius rise in temperature and 10–20 per cent change in rainfall would spark a 20 per cent reduction in produce like rice, beans and corn, which are staple crops for many Central American and Caribbean countries.

In the face of all this Fuller remains remarkably optimistic about his work at the CCCCC and the future for the region. As he rightly says: “You have to—what’s the alternative?”

In the next issue of Caribbean Beat, James Fuller examines some of the measures being put in place to help the region adapt to the potential impact of climate change.