Climate Change Effect On Coral Reefs

Coral reefs and climate change
Research on the current and future impacts of human-induced climate change on reef-building corals is causing scientists and managers to become increasingly concerned about the future of coral reefs.

A healthy reef ecosystem literally buzzes with sounds, activity and colors and is populated by incredibly dense aggregations of fish and invertebrates. A coral reef can contain tens of thousands of species and some of the world’s most dense and diverse communities of vertebrate animals.



Unfortunately, very few remaining coral reefs resemble this pristine condition; on most, corals and fishes are much less abundant than they were only a few decades ago.

Climate Change and Coral Loss
There are many causes of local and global coral loss but human-induced climate change is one of the main and undeniable threats rather than the natural climate change. Climate change is having negative effects on coral populations via at least three mechanisms.

First, ocean warming is directly reducing coral cover through coral bleaching. Reef-building corals contain plant-like organisms called zooxanthellae that live symbiotically within their tissue. Zooxanthellae provide their coral host with food and oxygen and in return, the zooxanthellae receive nutrients, carbon dioxide, and an enemy-free shelter. This symbiotic relationship evolved tens of millions of years ago and has been critical to the success and evolutionary radiation of corals and to the development of reef ecosystems.

When summertime water temperatures are just a degree or two warmer than usual for a few weeks, this critical yet delicate symbiotic relationship breaks down and the zooxanthellae are expelled, often leading to the coral’s death. (The greater the magnitude or duration of the warming, the greater the mortality and effect on coral populations.)
The phenomenon is called “coral bleaching” because the coral animal appears to turn white after the zooxanthellae loss. This is because without their zooxanthellae symbionts, which contain various photosynthetic pigments, corals are nearly transparent and the white, external calcium carbonate skeleton that the coral polyps live on becomes plainly visible.

Carbon dioxide, methane, and other greenhouse gases trap heat, leading to global warming. For example, in Palau, more than 90% of the corals on some reefs bleached and at least 50% perished. Even some isolated reefs were impacted. In the Maldives, in the east Indian Ocean, bleaching caused coral cover to plummet to only about 5%.

Ocean warming can also indirectly kill corals by magnifying the effects of infectious diseases, which are one of the primary causes of coral loss, particularly in the Caribbean. The number, prevalence, and impacts of diseases of corals and many other types of marine animals have been increasing over the last 20-30 years. The severity of marine diseases could increase with temperature for several reasons. Because elevated water temperature causes corals physiological stress, it can also compromise their immune system, potentially making them more susceptible to infections. Additionally, increased temperature could also benefit bacterial and fungal pathogens, making them more fit and/or virulent.

The third and in many respects the greatest concern in the longer term, is that global change is causing the world’s oceans to become more acidic. By burning immense amounts of fossil fuels, humans, particularly North Americans, are rapidly increasing the concentration of carbon dioxide (CO2) in the atmosphere (by roughly 30% to date). A quarter of the CO2 produced by the burning of fossil fuels enters the ocean and reacts with water to form carbonic acid, acidifying the ocean.

We have already lowered the pH of the ocean by about 0.1 unit which makes it more difficult and energetically costly for corals to secrete their calcium carbonate skeleton. Several experiments have demonstrated than even modest decreases in pH can slow coral growth, which will cause and compound a number of other problems.

Coral populations might also recover more slowly from other climate change-related stressors like bleaching and infectious disease or from natural disturbances and mortality agents like storms or predation.

This post is a summary of the article written at Encyclopedia of Earth website. Read the complete article at http://www.eoearth.org/article/Coral_reefs_and_climate_change webpage.

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Causes Of Natural Climate Change In The Past

In this post, I will discuss about the natural climate change contributors in the past, and still contributing big nowadays. This is just a summary post of global warming and natural climate change in the past article.

Solar activity
Solar variations have been the major driver of climate change over the past 10,000 years. Similarly, solar activity was higher during the Medieval Warm Period.
However, the correlation between solar activity and global temperatures ended around 1975. At that point, temperatures started rising while solar activity stayed level. This led a team of scientists from Finland and Germany to conclude "during these last 30 years the solar total irradiance, solar UV irradiance and cosmic ray flux has not shown any significant secular trend, so that at least this most recent warming episode must have another source." More on the sun & global warming.

Milankovitch cycles
Earth's climate undergoes 120,000 year cycles of ice ages broken by short warm periods called interglacials. The cycle is driven by Milankovitch cycles. Long term changes in the Earth's orbit trigger an initial warming which warms the oceans and melts ice sheets - this releases CO2. The extra CO2 in the atmosphere causes further warming leading to interglacials ending the ice ages.
The current trend of the Milankovitch cycle is a gradual cooling down towards an ice age.

Volcanoes
Volcanic eruptions spew sulfate aerosols into the atmosphere which has a cooling effect on global temperatures. These aerosols reflect incoming sunlight, causing a 'global dimming' effect. Strong volcanic activity exacerbated the Little Ice Age in the 1800's.

Summary
The usual suspects in natural climate change - solar variations, volcanoes, Milankovitch cycles - are all conspicuous in their absence over the past 3 decades of warming. This doesn't mean by itself that CO2 is the main cause of current global warming - you don't prove anthropogenic warming by eliminating all other options. But the primary causes of commonly cited climate change in the past have played little part in the current warming trend.
As for CO2, empirical observations show that CO2 has a warming effect as a greenhouse gas, CO2 is increasing in the atmosphere and the expected warming you would get from greenhouse gases is occurring.

Further explanation and information will be posted here. I suggest that you stay tuned for more updates. Meanwhile, read the whole article prior to this post at global warming and natural climate change in the past webpage.

Climate Change Effect In Philippines

Climate change in the Philippines is really a big issue. What I am trying to say is, Philippines is now experiencing major effects of this natural climate change.

Rainy season comes early, almost in an unexpected situation. Landslide are being reported from provinces. Flash floods is also a major problem.

Philippines Climate Change Extreme Effects - Image by knicko347

El Niño and La Niña is almost a normal thing now in the Philippines. Although the local government as well as other organizations are doing their best to bring back the good old days (which is almost impossible), still, it wasn't good enough.

What the Philippines really need for this natural climate change and those calamity brought by the climate change is the human cooperation and help.

People will often say, how can I help? I am just a normal person working all day for my family? Well a little help from this people can do a big change in the future. A typical family can help by limiting the usage of major contributors of pollution, specially plastic and styrofoams. Also, teaching family members not to throw garbage anywhere, specially at rivers and lakes may also help.

Ah, there are so many things that we can do to lessen up the bad effect of climate change. Will be posting more of it soon.

Major Causes of Climate Change

As previously stated, causes of climate change can be categorized in two. The natural and human causes. Let us take a look on each of them.

Natural Causes or Contributors

Some of the major contributors on these natural causes are continental drift, volcanoes, ocean currents, the earth's tilt, and comets and meteorites.

This drift also had an impact on the climate because it changed the physical features of the landmass, their position and the position of water bodies. The separation of the landmasses changed the flow of ocean currents and winds, which affected the climate.

Volcano Eruptions
When a volcano erupts it throws out large volumes of sulphur dioxide (SO2), water vapour, dust, and ash into the atmosphere. Millions of tones of sulphur dioxide gas can reach the upper levels of the atmosphere (called the stratosphere) from a major eruption. The gases and dust particles partially block the incoming rays of the sun, leading to cooling. Sulphur dioxide combines with water to form tiny droplets of sulphuric acid. Movement of aerosols north and south is always much slower.

As an example, Mount Pinatubo, in the Philippine islands erupted in April 1991 emitting thousands of tones of gases into the atmosphere. Volcanic eruptions of this magnitude can reduce the amount of solar radiation reaching the Earth's surface, lowering temperatures in the lower levels of the atmosphere (called the troposphere), and changing atmospheric circulation patterns. Significant weather-related disruptions occurred in New England and in Western Europe with killing summer frosts in the United States and Canada.

Earth's Movement
The earth makes one full orbit around the sun each year. In the other half when it is winter, the earth is tilted away from the sun. Changes in the tilt of the earth can affect the severity of the seasons - more tilt means warmer summers and colder winters; less tilt means cooler summers and milder winters.

Body of Water Currents
The oceans are a major component of the climate system. They cover about 71% of the Earth and absorb about twice as much of the sun's radiation as the atmosphere or the land surface.

Winds push horizontally against the sea surface and drive ocean current patterns.
Certain parts of the world are influenced by ocean currents more than others. The coast of Peru and other adjoining regions are directly influenced by the Humboldt current that flows along the coastline of Peru. The El Niño event in the Pacific Ocean can affect climatic conditions all over the world.

Another region that is strongly influenced by ocean currents is the North Atlantic. If we compare places at the same latitude in Europe and North America the effect is immediately obvious. The rest of the Arctic Ocean, even though it is much further south, remains frozen.

Human causes

The Greenhouse Effect
Carbon dioxide is undoubtedly, the most important greenhouse gas in the atmosphere. Changes in land use pattern, deforestation, land clearing, agriculture, and other activities have all led to a rise in the emission of carbon dioxide.

Methane is another important greenhouse gas in the atmosphere. Methane is also released from rice or paddy fields that are flooded during the sowing and maturing periods. When soil is covered with water it becomes anaerobic or lacking in oxygen. Under such conditions, methane-producing bacteria and other organisms decompose organic matter in the soil to form methane. China and India, between them, have 80-90% of the world's rice-growing areas.

Humans Daily Contributions
All of us in our daily lives contribute our bit to this change in the climate. All our gadgets run on electricity generated mainly from thermal power plants. These thermal power plants are run on fossil fuels (mostly coal) and are responsible for the emission of huge amounts of greenhouse gases and other pollutants.

- We generate large quantities of waste in the form of plastics that remain in the environment for many years and cause damage.
- Timber is used in large quantities for construction of houses, which means that large areas of forest have to be cut down.

Because the land area available for agriculture is limited (and in fact, is actually shrinking as a result of ecological degradation!), high-yielding varieties of crop are being grown to increase the agricultural output from a given area of land. Pollution also results from the run-off of fertilizer into water bodies.

We must act now to be able to limit and decrease this climate change causes. I know we can’t stop the natural ones but the human causes; I think we can do something about it. Besides, we humans are the high contributors and will be highly affected by this climate change.

Natural Climate Changes

Natural climate changes is a state of having a sudden change in a weather or climate condition. Experts and other concerned organizations and/or citizens believes that this kind of changes is an effect of the global warming condition.

This kind of weather condition can be reduced or minimize if we will only become much more responsible person or individual.

Climate change may result from both natural and human causes. The percentage of human causes has been increasing during the past few decades. It is due to the growing population as well as the fast growing industry we have in our world.

We can minimize the effect of this man caused - climate change if we will become a responsible individual or person.

But first we need to know what are the top or the common contributors or contributions made by man to this climate changes. As we all know, smoke coming from our vehicles, those gas coming from our houses and industrial plants are the most and top contributors all the time.

Image Credits To: CombatClimateChange.ie

Natural climate changes must be closely studied for us to be able to help our planet to survive this climate changing condition. Let us all take action in this climate situation!