Impact of Global Climate Change

Global climate changes have adverse impact in numerous ways. We can include the impact and can summarize under following headings.

I. Impact of temperature rise

     II.           II.  Sea level rise

   III.            III. Impacts of high intensity of rainfall 

Climate change will significantly alter weather patterns and terrestrial and aquatic ecosystems. It will attack socioeconomic systems that human welfare depends. 

Impacts of Temperature rise

Land Resources

Changes in temperature caused by climate change will affect the geographic distribution of biomass. Such change affects species of plants and animals growth and reproductive cycle. Forest have important role in climate change. The vegetation of forest ecosystems account for 80% of carbon above ground; and the soil beneath forests captures 40% of soil carbon (Melillo et al 1990; Dixon et al 1994; Watson et al. 1996). Forests work as a carbon sink. 

In 2005, the Amazon was struck by a ''one-in-100 year'' drought which resulted in an estimated five billion tonnes of CO₂ being released into the atmosphere.

Climate changes add an additional stress to the adverse effect of deforestation in the Amazon rainforest. This impact cause biodiversity losses, reduce rainfall and runoff within and beyond the Amazon basin, and affect the global carbon cycle. Temperature rise affect the ground temperatures, evapotranspiration, surface roughness, albedo, cloud formation and precipitation. Increases in temperature and atmospheric carbon concentrations are increase the net primary productivity of temperate forests. It leads to wild fire and pests will counter these effects. Furthermore, lands that border on deserts – mainly arid, semiarid, and dry sub humid areas will be undergo irreversible desertification. 

Water Resources

Increase in atmospheric temperature affects hydro power generation. It accelerated the evaporation in water reservoirs and reduces the energy usage. Mountain snow cover and glaciers are melting rapidly. There by it affecting the magnitude and seasonally of river flows that supply water to many hydro powers. 

Runoff and ground water flow into lakes and streams also altered by an increase in our temperature. Hydrological variations could affect the biological, bio-geochemical, and hydrological functions of wetlands. It produces several useful functions, such as recharging of aquifers, sediment retention, waste processing, and carbon storage (Matthews and fung 1987). Climate change impact the ground water usage in two ways, (i) reduce the total volume of ground water recharge, (ii) Groundwater in limestone region affected by saltwater intrusion. During the drought seasons groundwater has an important role in determined the stream flow. Increasing air temperature could affect these functions. 

Food production 

Higher temperature increases the evapotranspiration and reduces the soil moisture. These effects on agriculture industry will have a negative impact on production and distribution systems. It destroys economically important crops. Climate change more vulnerable for livestock systems than crop systems. Extended droughts followed by periods leads to land degradation.  

Human health

Climate change would be increase heat – related deaths and illness particularly in region with high population densities and poor infrastructure. Asthma, allergic disorders and cardiorespiratory diseases occur due to changes in pollens and spores and to temperature increases. 

Food and water shortages would exacerbate hunger, malnutrition. There by humans become more vulnerable to non-climate-related causes of diseases and death. Another consequence of rise in temperature is heat waves. Heat puts more stress on weak hearts and bodies. One notable example is Europe experienced worst heat wave in 2003 more than a century. 

Sea-level rise

Climate change has significant impact on sea level rise. Global warming is the dominant factor and accelerated the sea level rise. Due to sea level rise wetlands and lowlands would be displaced, shorelines eroded, estuaries and fresh water aquifers rendered more saline due to saltwater intrusion, and nutrient and sediment transport affected.  

Low – lying island states and atolls are especially vulnerable to climate change and associated sea level rise. Much of the islands land area rarely exceeds 3-4 m above present mean sea level. Example – The Bahamas, Kiribati, the Maldives, the Marshall islands. Another impact is salt water intrusion. Large delta regions of Bangladesh, Myanmar, Vietnam and Thailand are exposed to this threat. It also cause wide spread destruction of wetlands and affect paddy fields. Sri Lanka has already experiencing approximately 15,000 hectares of paddy fields in the Galle district. 

Over the past few decades’ coastal wetlands, salt water marshes and mangroves systems have disappeared at a rate of 0.5 to 1.5% per year in some regions. Marine ecosystems, coral reef contain large biological diversity. They are also getting threatened. A temperature increase cause bleaching of coral reefs. It affects their reproductive functions and lead to increased mortality. Sea level rise blocks the runoff of flat land river in to the ocean. It increase the risk of floods in their basins (e.g., in the Argentine pampas). 

Melting snow is another major reason for sea level rise. In the Arctic Ocean, sea ice is melting fast. In September 2007 Arctic sea ice was 39% below the long-term average. The rate of sea ice decline between 1979 and 2007 was about 10% per decade. A warmer pattern of Arctic will also affect weather patterns and flood production around the world. Antarctic Peninsula is also losing ice. Melting glaciers and land – based ice sheets also contribute to rising sea levels. Lose of sea ice threatens marine ecosystems and cause a reduction in food for polar bears. 

Impacts of high intensity of rainfall

Increasing temperatures tend to increase evaporation and it leads to more precipitation (IPCC, 2001). High intensity of rain fall causes cyclones, low pressure, monsoon, thunder and lighting. 

Heavy rainfall will degrade soil structure and reduce the soil’s capacity to circulate organic matter (bullock and Le Houerou 1996). It increased the leaching which leads to acidification and nutrient loss. Extreme events adversely affect range lands and agricultural production. 

Tropical storms and hurricanes are produce stronger winds and increased rainfall. They damaged infrastructure and communication through increased flooding and landslides. Those living in shanty towns in areas around large cities are more vulnerable. It also leads to siltation in reservoirs. Indirect effects through impacts on other sectors such as water and food supply, transportation, energy distribution and sanitation services. 

It increases the geographical distribution of vector borne diseases (e.g., malaria, dengue, chagasi) and infections diseases (e.g., cholera). Mainly tropical, subtropical and poorly protected temperate zone population exposed to malaria.

Conclusion

The effects of global climate change become seriously and cause regional increases in floods and droughts, inundation of coastal areas, high temperature events, and fires, out breaks of pests and disease, damage to ecosystems, threats to agricultural production and affect the human health and safety. 

Climate models predict that Greenhouse gases (GHSs) emissions from any range of future economic activities will lead to increasing concentrations of atmosphere GHGs. it cause significant changes in global and regional temperatures, mean sea level and precipitation. 

References ; 

(1) Kevin T. Pickering an Lewis A.Owen (1997); An introduction to global environmental issues; London and New york 

(2) Catrinus J. Jepma and Mohan Munasinghe (1998); Climate change policy (facts, issues, and analyses); Cambridge university press. 

(3) Polar Meteorology, understanding global impacts; WMO - No. 1013; 2007; World Meteorology Organization

(4) https://www.e-education.psu.edu/geog438w/node/240

(5) http://www.coolearth.org/306/news-32/rainforest-news-155/amazon-rainforest-in-danger-of-contributing-to-climate-change-1571.html

Trends in global climate change

Temperature changes 

Recent studies indicated the evidence of climate change. A range of climate indicators show that the twentieth century is warmer than any other century. Global mean surface temperatures have risen by 0.74oc ± 0.18oc over the last 50 years than over the 100 years. The instrumental record of global surface temperature recorded 1998 and 2005 as warmest years. Mean surface temperatures increasing markedly from 1900 by 1.2 – 1.4 ^oF. During this period there was a rapid temperature increase in 1910-1930 and 1970’s. There have been observed spatial variations in temperature. For example, greater warming observed over mid latitude continental areas during winter and spring. 

Lower – tropospheric temperatures showed slightly greater warming rates over the period 1958 to 2005. Lower stratospheric temperatures are cooling since 1979. Tropospheric water vapour is increasing after 1976’^s by higher temperatures over both land and ocean. 

Droughts have become common in tropics and sub tropics since the 1970. Declined land precipitation and increased temperatures are enhancing the evapotranspiration and drying. The regions where droughts have occurred determined by the changes of sea surface temperature. These changes associated through atmospheric circulation and precipitation. Australia and Europe recent droughts events are accompanying with the extreme nature of high temperatures and heat waves. Temperature increases accelerated the wildfire. Worst wildfire occurred in April 2009 at Southern California. It destroyed 8,100 hectares land area.

Changes in precipitation 

Precipitation has shown increased trend over land north of 30⁰ N over the period 1900 to 2005. In tropics downward trends dominate since the 1970’s. Tropical values become significantly wetter in eastern parts of North and South America, Northern Europe, and Northern and central Asia. Drier in the Sahel, the Mediterranean, Southern Africa and parts of Southern Asia.

Records of land surface precipitation show increase trend over much of the Northern hemisphere’s mid and high latitudes by 0.5 to 1percent per decade. In Sub-tropical land areas, precipitation has slightly declined by 0.3% per decade. There is also evidence of precipitation increases over the tropical oceans and tropical land areas. In Vietnam heavy rain and floods occurred in October 2008. The frequency and intensity of precipitation also varied over the annual, decadal and multi-decadal time scales. 

Oceanic climate change & sea level rise 

The rise in global mean sea level is another indicator of global warming. This warming events result from thermal expansion of the oceans and the melting of glaciers and ice sheets. The Tide gauge measurements suggest that sea level has risen worldwide approximately 6-8 inches during last century. During the period of 1961-2003 mean sea level raised by 1.8 ± 0.55 mm. 

According to the National Aeronautics and space Administration’s (NASA) Earth observatory, satellite measurements estimate that sea level has been rising at a rate of 9 to 13 inches per century since 1993. 

Intense tropical cyclone activity has increased since about 1970. Sea surface temperature and other critical variables have influence on tropical thunder storm and tropical storm development. For example, the Atlantic basin was extremely active with number of tropical storms system including hurricanes between the periods of 1995-2005. Recently strongest tropical cyclone occurred in Madagascar in February 2008. 

Changes in Snow

The cryosphere have complex linked with the surface energy budget, the water cycle, sea level change and the surface gas exchange. Recent decreases in ice mass are related with rising surface air temperatures. Especially this changes observed in north of 65⁰N. 

The volumes of Green land, Antarctica, Artic and Himalaya Ice sheets are start to melt rapidly. According to Artic researches ice sheet has been 2m thicker and shrink as 42% and that region lost 6% glacier ice sheet. Temperature increase 3⁰C over western part of the Antarctica over the past 50 years. Alaska lost 500 cubic mile of glaciers over the past 50 years. 

The cryosphere on land stores about 75% of the world’s fresh water. Changes in ice mass have contributes recent sea level changes and affect the fresh water availability in many mountains and surrounding regions. The high albedo of snow has an important influence on the surface energy budget and on earth’s radiative balance (e.g., Groisman et al, 1994). 

 References :

(1) Kevin T. Pickering an Lewis A.Owen (1997); An introduction to global environmental issues; London and New york 

(2) Catrinus J. Jepma and Mohan Munasinghe (1998); Climate change policy (facts, issues, and analyses); Cambridge university press.

(3) http://www.unep.org/pdf/ccScienceCompendium2009/cc_ScienceCompendium2009_ch1_en.pdf

(4) http://www.arctic.noaa.gov/reportcard/sea_ice_ocean.html