Biological diversity, or simply biodiversity, is the variety of the Earth's species, or varying life-forms, the genes they contain, the ecosystems in which they live, and the ecosystem processes of energy flow and nutrient cycling that sustain all life.
The earth's biodiversity is a vital part of the natural wealth that helps keep us alive and supports our economies.
The rich variety of life on earth has always had to deal with a changing climate. The need to adapt to new patterns of temperature and rainfall has been a major influence on evolutionary changes that produced the plant and animal species we see today.
Human pressure on ecosystems are causing changes and losses at rates not seen historically.
People are changing ecosystems more rapidly and more extensively than over any other period in human history. Climate change adds yet another pressure on natural ecosystems.
What makes climate change a threat for biodiversity?
Variation in the climate is perfectly compatible with the survival of ecosystems and their functions, on which we each depend for the essentials of life. Yet, according to the Millennium Ecosystem Assessment (MA), climate change now poses one of the principal threats to the biological diversity of the planet, and is projected to become an increasingly important driver of change in the coming decades.
There are several reasons why plants and animals are less able to adapt to the current phase of global warming. One is the very rapid pace of change.
It is anticipated that over the next century, the rise in average global temperatures will be faster than anything experienced by the planet for at least 10,000 years.
Many species will simply be unable to adapt quickly enough to the new conditions, or to move to regions more suited to their survival.
Equally important, the massive changes humans have made to the landscape, river basins and oceans of the world have closed off survival options previously available to species under pressure from a changing climate.
There are other human-induced factors as well.
Pollution from nutrients such as nitrogen, the introduction of alien invasive species (species not native to the region or country, often with the potential for out-competing native species) and the over-harvesting of wild animals through hunting or fishing can all reduce the resilience of ecosystems, thus diminishing the likelihood that they will adapt naturally to climate change.
There is evidence that climate change is already affecting biodiversity and will continue to do so. Consequences of climate change on the species component of biodiversity include:
* Changes in distribution,
* Increased extinction rates,
* Changes in reproduction timings, and
* Changes in length of growing seasons for plants.
This has major implications not just for the variety of life on our planet, but also for the livelihoods of people around the world.
Since frogs rely on water to breed, any reduction or change in rainfall could reduce frog reproduction.
Moreover, rising temperatures are closely linked to outbreaks of a fungal disease that contributes to the decline of amphibian populations.
In Africa, pressures from longer dry periods and shrinking living spaces are making elephants highly vulnerable to climate change.
Australia's Great Barrier Reef could lose up to 95 per cent of its living coral by 2050 because of changes in ocean temperature and chemistry.
In the Arctic, shorter periods of sea ice coverage endanger the polar bear's habitat and existence by giving them less time to hunt.
Climate fluctuations in North America reduce plankton populations, the main source of food of the North Atlantic right whale. Only about 300 whales of this species remain at present and the reduced availability of food because of climate change is becoming an increasing cause of their death.
Warmer temperatures in the Pacific regions could reduce the number of male sea turtle offspring and threaten turtle populations.
The sex of sea turtle hatchlings is dependent on temperature, with warmer temperatures increasing the number of female sea turtles.
Why should we be concerned?
Islands such as ours are often characterized by a very rich biodiversity, upon which local people rely economically. Island ecosystems are also very fragile and especially vulnerable to climate change because island species populations tend to be small, localised, and highly specialised. Thus they can easily be driven to extinction.
The main threat to island ecosystems is the observed and projected rise in sea level.
Other risks include an increased frequency and/or intensity of storms such as those seen in Fiji earlier this year, reductions in rainfall in some regions, and intolerably high temperatures.
Increases in sea surface temperatures and changes in water chemistry can cause large-scale coral bleaching, increasing the probability of coral death.
The tourism sector, which is an important source of employment and economic growth for Fiji, will likely be affected through loss of beaches, flooding, and associated damage to critical infrastructures.
nDevika Raj is a member of Project Survival Pacific - Fiji's Youth Climate Change Movement. For further information and clarification e-mail firstname.lastname@example.org