Md. Zillur Rahaman :
The planet’s average surface temperature has risen about 1.62 degrees Fahrenheit (0.9 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide (CO2) and other human-made emissions into the atmosphere. Most of the warming occurred in the past 35 years, with the five warmest years on record taking place since 2010.
Global warming is the long-term rise in the average temperature of the Earth’s climate system. It is a major aspect of climate change and has been demonstrated by direct temperature measurements and by measurements of various effects of the warming. Global warming and climate change are often used interchangeably.
But more accurately, global warming is the mainly human-caused increase in global surface temperatures and its projected continuation, while climate change includes both global warming and its effects, such as changes in precipitation. While there have been prehistoric periods of global warming, many observed changes since the mid-20th century have been unprecedented over decades to millennia.
Scientists have been studying the relationship between global climate and carbon in the atmosphere for more than a century, with a growing understanding of the massive, inadvertent experiment we’re conducting with our planet. The picture is clear: carbon dioxide released into the air by the burning of fossil fuels-oil, gas, and coal-is changing the world’s climate.
The evidence comes from measurements taken by thousands of researchers, working in all domains of physical and biological sciences, gathering data with a host of different instruments over years or often decades.
Their data paint an increasingly detailed portrait of how our planet is changing. One can explore a small part of the scientific data from different realms being affected by climate change- the Atmosphere, Oceans and Water, Ice, and Land and Living Systems.
Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that the Earth’s climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that current warming is occurring roughly ten times faster than the average rate of ice-age-recovery warming.
The Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report concluded, “It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century”. The largest human influence has been the emission of greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to 1.7 °C in a moderate scenario, or as much as 2.6 to 4.8 °C in an extreme scenario, depending on the rate of future greenhouse gas emissions and on climate feedback effects. These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing.
The effects of global warming include rising sea levels, regional changes in precipitation, more frequent extreme weather events such as heat waves, and expansion of deserts. Ocean acidification is also caused by greenhouse gas emissions and is commonly grouped with these effects even though it is not driven by temperature. Surface temperature increases are greatest in the Arctic, which has contributed to the retreat of glaciers, permafrost, and sea ice. Overall, higher temperatures bring more rain and snowfall, but for some regions droughts and wildfires increase instead.
Climate change threatens to diminish crop yields, harming food security, and rising sea levels may flood coastal infrastructure and force the abandonment of many coastal cities. Environmental impacts include the extinction or relocation of many species as their ecosystems change, most immediately the environments of coral reefs, mountains, and the Arctic.
Societal responses to global warming include mitigation by emissions reduction, adaptation to its effects, and possibly climate engineering. Countries work together on climate change under the umbrella of the United Nations Framework Convention on Climate Change (UNFCCC), which entered into force in 1994 and has near-universal membership.
The ultimate goal of the convention is to “prevent dangerous anthropogenic interference with the climate system”. Although the parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2 °C in the Paris Agreement of 2016, the Earth’s average surface temperature has already increased by about half this threshold and current pledges by countries to cut emissions are inadequate to limit future warming.
Recent US President Donald Trump’s position on climate change has been in the spotlight again, after he criticised “prophets of doom” at the World Economic Forum in Davos.
At the event, which had sustainability as its main theme, and activist Greta Thunberg as its star guest, Mr Trump dismissed “alarmists” who wanted to “control every aspect of our lives” – while also expressing the US’s support for an initiative to plant one trillion trees.
If one judges Donald Trump based on his words alone, his views on climate change appear contradictory, confusing and mind-boggling. He has called climate change as “mythical”, “nonexistent”, or “an expensive hoax” but also subsequently described it as a “serious subject” that is “very important to me”.
In 2012, he famously said climate change was “created by and for the Chinese in order to make US manufacturing non-competitive” – something he later claimed was a joke. He regularly repeated claims that scientists has rebranded global warming as climate change because “the name global warming wasn’t working”
The USA has officially skipped off the Paris climate agreement, striking a serious blow to the global pact that seeks to limit global warming to well below 2C. The US is the first country to pull out of the accord with effect from 2016 which was a top policy priority for the Obama administration. The move to exit brought swift condemnation globally from climate advocates. USA formally notified the UN before announced that the US would exit the accord as it would hurt the US economy.
The environmental effects of global warming are broad and far-reaching. They include effects on the oceans, ice, and weather and may occur gradually or rapidly.
Many regions have already seen increases in warm spells and heat waves, and it is virtually certain that these changes will continue over the 21st century. Extremely wet or dry events within the monsoon period have increased in India and East Asia.
It is to be mentioned here that many developed countries including USA are avoiding willfully the Kyoto Protocol 1997 since long and these countries are the most responsible for greenhouse effect emissions across the world. As a result, the developing and underdeveloped countries beside the sea level are on the vulnerable stage of climate change due to carbon emission of these industrial nations. The children protest, led by Greta Thunberg, a Swiss girl, of climate change impact gave a clear message to the world leaders who are responsible for greenhouse emissions.
A growing number of countries in Europe are vowing to cut their emissions more quickly. The UK and France have both pledged to bring their emissions down to net zero by 2050 but the US exist is a big blow of climate change pact. Certainly it will affect mostly the developing countries like Bangladesh and so the developing countries should put pressure on USA regarding Paris protocol.
(Md. Zillur Rahaman, Banker and Freelance Writer. The different sources of information are acknowledged with gratitude by the writer)
