Increasing temperature on earth’s atmosphere due to greenhouse gas emission is known as global warming. Higher concentration of CO2 is a major factor for increasing temperature on earth. However, human induced carbon emission is higher than natural emission. The Ocean water absorbs excess temperature is and it will leads to Ocean warming. So that land and water are under threat of rising temperature and associated impacts. Maintaining the temperature below 2°C is a major urgency because it is a major factor for climate change. The climate change affects the earth’s natural climate and seasons. It will affect the socio-economic, ecological and cultural development in society.
October 2018, the UN Intergovernmental Panel on Climate Change (IPCC) published its fifth report on climate change. This report revealed a comprehensive assessment of sea level rise and its causes, over the past few decades. The climate scientists were examined the cumulative CO2 emissions since pre-industrial times and provides a CO2 budget for future emissions to limit warming to less than 2°C.
a. Important findings from IPCC report:
- The average global temperature increased
by 0.85 °C → 1880 to 2012
- The global average sea level rose
by 19 cm as oceans → 1901 to 2010
- 1–2° C increase in global mean temperature above the 1990 level (about 1.5–2.5° C above the pre-industrial level).
- A average sea level rise predicted to be 24–30 cm by 2065 and 40–63 cm by 2100 relative to the reference period of 1986–2005
Based on these findings, the climate scientists and experts were warned the world to limit the temperature below 1.5°C within 2030. For this, there is only 12 years is remaining to mitigate the increasing temperatures. If didn’t take it as serious and not act against these issues, its impacts will be very catastrophic. A small increase of temperature may be leads to drought, floods, extreme heat, diseases and death of organisms. Hundreds of millions of people will affect by poverty and lose their homes and land due to extreme climate events.
Fig.3. The world after sea level rise (Ref.http://www.climatecentral.org/)
Impacts of higher temperature in Ocean
Half-degree difference in temperature may affect the ocean and its different type of habitats and biodiversity. Increasing temperature will leads to higher rate of ice melting in Polar regions. This will lead to the sea level rise, drowning of small island nations and low lying coastal zones, complete destruction of seagrass meadows. The warm ocean water affects marine biodiversity. Especially, the coral reefs are vulnerable to ocean acidification and coral bleaching. Lot of organisms is depending coral reefs for their life. Coral reefs are biodiversity hotspots in Ocean. Invertebrates, fishes, sea turtles and other organisms are living in coral reefs. Coral reefs are nursery ground of some organisms and fishes. The destruction of coral reefs will affect the productivity of ocean. It negatively affects the fishery resources. Ocean warming will affect the ocean biodiversity and lead to the migration, invasion or death of organisms in ocean. The increasing heat wave will affect all organisms in different ways. The difference in temperature will affect the metabolism and reproductive activities of marine organism. The variation of temperature may affect the spawning activities in these organisms due hormonal changes. The identification of their spawning seasons is difficult for them due to variation in climate or seasons. It will affect the reproductive activities in organisms. These all changes will lead to the changes in biodiversity and abundance and reason to the complete destruction of ocean food web.
Fig. 2 Totten Ice-Shelf- : melting-glacier-in-antarctica-could-raise-sea-levels-by-11-feet (Ref.2)
Impacts of higher temperature on socio-economic sector
The southern ocean is more productive than northern region. Fishery production is higher in this zone due to the higher primary productivity. The kelp forest ecosystems are hotspot of biodiversity in this region. The increasing rate of ice melting in Antarctic region will diminishes the primary productivity and fishery resources in Ocean leads to economic loss. Fish industries and fishing related jobs will reduce in world. Besides this, it will lead to food crisis due to unavailability of sufficient marine food.
The extreme climate incidents like tropical cyclones, typhoons and hurricanes will be a major reason for economic loss. The numbers and intensity of such storms will be higher than previous years. The El-nino and La-Nina phenomenon will leads to severe floods and drought in different parts of the world. This will affect the socio-economic development of human society. Sometimes the competition for resources will leads to conflicts between humans and animals in different places globally.
Impacts of sea level rise in coastal zone and small island nations
Sea-level rise is a major threat to the socio-economic and cultural aspects of human society. Similarly, Sea-level rise is always a reason for ecological problems in coastal zones. The small islands countries and island marine protected area will be drowned in sea water. The sea level rise affects the cultural monuments and sites in island nations and coastal zones. People will force to migrate from their homeland to other places due to loss of homes and farmlands etc. This maybe leads to the conflicts between different nations or states. Sometimes, it will leads to war between people or nations for the competition for utilization of resources. Lot of organisms and people will be refugees. The major cities in the coastal zones of different nations will be wiped out by sea level rise. This is a risk for global economy and humans in different ways.
The biodiversity in island nations are vulnerable to sea level rise. The climate change and sea level rise will be the reason for extinction of such flora and fauna from face of earth. Besides this, the sea level rise will affect the coastal wetlands and mangrove forests. The coastal zones of almost all nations are vulnerable to sea-level rise. Fishing industries and fishery related communities were mainly settled in coastal zones globally. They are vulnerable to sea level rise.
The seawater intrusion to the coastal zone is a major threat for coastal freshwater aquifers. The increasing salinity will affect the groundwater resources too. The higher salinity will affect the water and sediment quality in coastal habitat and its biodiversity. Salinity will affect the nutrients of sediments and destruct the sea grass meadows and vegetation.
The severe drought will occur in different places. The availability of clean drinking water is a major problem for humans. The water born related diseases will increase in these regions. Besides these, the emergence of new diseases is a major challenge for humans. Health sector need more money for research and development.
Fig.3 Sea-Level Rise and Its Impact on Coastal Zones.Vulnerable zones are marked as violet lines (Ref.3)
Limiting the temperature up to 2°C is a major challenge for world. It needs a global action to control the temperature. The following mitigation process is helpful to control the temperature.
- Reduce the carbon emission
- Reduce the animal and poultry farming for meat industry
- Promote the vegetarian diet
- Reduce the use of coal and fuels
- Reuse the materials in a sustainable way
- Stop ice drilling in polar regions
- Do public awareness
- Implementation of laws and regulation for better environmental management
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