Oceans as carbon sinks
Oceans are the largest carbon sinks on Earth. About one third of the carbon dioxide released by human activities is absorbed by oceans.
Oceans function as carbon sinks as a large portion of carbon is dissolved in the ocean water. Furthermore, phytoplankton and algae absorb dissolved carbon dioxide to carry out photosynthesis.
A portion of the carbon compounds found in oceans is buried in the seabed and is in the form of fossil fuels such as natural gas and oil.
A way to increase the photosynthetic activity of phytoplankton is to stimulate the growth of the phytoplankton and increase the phytoplankton photosynthetic rate.
Forests as carbon sinks
Forests are also important as carbon sinks. Atmospheric carbon dioxide is absorbed by the plants and used in photosynthesis. In forests, a large amount of carbon compounds is stored in trees.
When trees die, their remains may be buried deep in the ground.
After millions of years, these remains form coal – a fossil fuel.
Uncontrolled deforestation has damaging effects as the trees are removed and this leads to the reduction of carbon sinks.
When the cut trees are burnt, carbon stored in the plants is released in the form of carbon dioxide, contributing to global warming.
Kyoto Protocol
Kyoto Protocol requires participating industrialised countries to reduce their carbon emission. For example, according to this protocol, U.S should reduce its carbon emission by 7%. To achieve this, the U.S. would need to plant millions of fast-growing trees per year to reforest lands over a period of 40 years.
In 2001, the U.S. pulled out of the Kyoto Protocol. However, most other industrialised nations still collectively agreed to reduce their greenhouse emission to achieve an overall reduction of 5.2% for the period of 2008 to 2012. Singapore joined the Kyoto Protocol in 2006.
Greenhouse gases include carbon dioxide (CO2), methane (CH4) and nitrous oxides (N2O). But the main greenhouse gas that contributes to global warming is carbon dioxide released during the burning of fossil fuels.
In Singapore, the primary greenhouse gas is carbon dioxide generated from energy consumption.
In the effort to reduce energy consumption, Singapore has made it compulsory for all air-conditioners and refrigerators to be energy efficient.
Additional information: Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change. It was first adopted in 1997 in Kyoto, Japan, and it is aimed at reducing greenhouse gas emissions.