Starting from the primordial period of the universe, the so-called "Big Bang" evolved through various stages in its way and had passed billions of years with billions of galaxies, clusters and superclusters. The blue planet 'Earth' is a beautiful natural gift of our Milky Way Galaxy of the universe, which is fascinated with various natural resources. Over the centuries, numerous studies were carried out to understand the various geographical conditions and phenomena associated with our planet to fulfill the curiosity and many fundamental questions of mankind. The different layers of gases, commonly known as air, retained by Earth's gravity, surrounding the planet earth form the atmosphere and they are the key parameters that controls life on earth. While the term 'weather' refers to the short-term conditions of the atmosphere in a region, the term 'climate' reflects the typical weather conditions for an extended period of time in a certain specific region.
During the past centuries, a large amount of carbon dioxide (the main greenhouse gas) and other greenhouse gases (water vapour, methane, nitrous oxide etc) were released due to various man-made activities into the atmosphere, most of which were derived from burning fossil fuels required for the production of energy. The greenhouse gases act like a blanket surrounding the earth's atmosphere, trapping the heat inside it and causing it to warm. The climate changes as a result of this constant increase in temperature and thereby potentially affecting human health and the entire ecosystem. As per the annual report by Intergovernmental Panel on Climate Change (IPCC), as a result of climate change, the global mean sea level (GMSL) has been rising and accelerating continuously. In the last Interglacial period, GMSL was found to be 6-9 m higher, mainly due to the contribution from the Greenland and the Antarctic ice sheets. This is creating a huge disaster in the coastal areas. According to the IPCC report, GMSL will rise between 0.43 m to 0.84 m by the year 2100 and beyond this, the sea level will continue to rise for centuries due to continuous deep ocean heat uptake and is a major concern for many countries nearby coastal areas. Not only the rising water level, the warming ocean is also affecting marine organisms at multiple trophic levels impacting fisheries with implications for food production and human communities.
Apart from the rising sea level, warming up the land has occurred at a faster rate and this has had observable impacts on the land system and the related ecosystem. As per the IPCC report, the average temperature over land for the period 2006-2015 was 1.53°C higher than for the period 1850-1900, and 0.66°C larger than the equivalent global mean temperature change. These warming temperatures of land have altered the beginning and ending of growing seasons, reduced the yield of crops, resulted in shortage of freshwater and have put the entire biodiversity under further stress and increased tree mortality.
From the above discussion, it can be clearly inferred that the increasing climate-related risk and its impact on natural and human systems have become a major concern as it is going to create havoc in the near future. Therefore, it has become very essential to think and take immediate and appropriate steps to reduce the production of greenhouse gases. International collaboration and political agreement for lessening the emission of greenhouse gases should be taken. The Paris agreement on climate change is one of such steps to cut out the emission of greenhouse gases but still has major concern on the rising global warming. It is extremely important to have rapid reductions in anthropogenic greenhouse gas (GHG) emissions that restrict global warming and would greatly reduce the negative impacts of climate change on land and marine ecosystems. Not only at the national and international level, but every citizen should be well aware of this phenomenon and take small steps to reduce the emission of greenhouse gases as far as possible, for a sustainable environment-friendly ecosystem.