Climate change : Biggest challenge in 2020s

Debapriya Mukherjee
Environmental crises particularly climate change have become depressingly familiar in the past decade. Based on scientific evidences it is expected that 2020 would be the year when the planet will start to feel the heat as something real and urgent. Global heating passed the 1.5oC mark a couple of years earlier and is now accelerating towards 3oC by the end of the century. For a while, marathons, World Cups and Olympics were moved to the winter to avoid the furnace-like heat in many cities. The positive climate feedbacks are not limited to physics, but stretch to economics, politics and psychology. The poorest will be worst affected, though they have the least responsibility for the climate crisis.  Thereby we should not wait for the earth to start simmering. Now appropriate knowledge and a renewed dedication to social and environmental responsibility, the 2020s must be transformational.
Climate change is getting unprecedented attention particularly during election campaign with a commitment from many of the political leaders all over the world to ensure zero emission within the stipulated time. They are mainly responding to the threats posed by a rapidly warming climate, the economic opportunities in switching to clean energy and the increasing concern of millions of people on the streets to demand stronger action. Sadly decades of scientific research could not motivate many political leaders sufficiently to act though the world is screaming out for action. In this context we can refer the populist President of Brazil who slashed federal funding for science, and in July accused his own government’s scientists of lying about a spike in deforestation in the Amazon — the world’s largest rain forest, which is home to one in ten known species. In the United States, President Donald Trump continued his efforts to dismantle environmental regulations. As a follow up action the US Environmental Protection Agency (EPA) finalized a series of action plan to relax limits not only on greenhouse-gas emissions from power plants but also on other sectors (automobiles). Unfortunately, in November, the administration started the official process of pulling the United States out of the Paris agreement. In India PM Narendra Modi emphasized on the guiding principle "need and not greed” to tackle climate change. But in reality, the indiscriminate use of natural resources by giant companies without any concern to the environment in the name of development   for the particular year outstrips Earth's capacity to regenerate those resources that year. The cost of this overspending includes deforestation, soil erosion, overfishing, and CO2 build-up in the atmosphere, which leads to global warming, more severe droughts, wildfires and other extreme weather events. Even expenditure incurred for the welfare of politicians, bureaucrats and senior officers; for organizing seminars, meeting and many more is the clear evident of wastage of natural resources and increased carbon emission. So our PM’s believe  -- “an ounce of practice is worth more than a ton of preaching”  did not raise any awareness to climate action despite the highest burden of death from air pollution and other adverse impact on environment and human. More such examples can be cited in this context.
This major barrier to climate action may be attributed to some really powerful and well-funded, fossil-fuel interest companies. Now only option to overcome this barrier is to have the same level of people power that can put much greater pressure on our political leaders to ignore these companies who are speaking louder than the voices of people. It is real and it is already happening. This climate change is not happened by accident. Human-caused climate change has already been proven to increase the risk of floods and more erratic precipitation, and rising sea levels over medium to long timeframes, extreme weather events (e.g., storms, prolonged drought, and heat waves) and wildfires (the devastating blazes in Siberia and the Amazon this year) with implications for humans, animals and the environment. As reported, globally the number of floods and heavy rains has quadrupled since 1980 and doubled since 2004. Extreme temperatures, droughts and wildfires have also more than doubled in the last 40 years. San Francisco, British Columbia and Delhi experienced all-time record June temperatures this year, indicating heat waves are beginning anew in the Northern Hemisphere this summer and are 30 times more likely due to climate change. Extreme weather particularly the unusual number of hot and cold days during the preceding years even in mountain areas as observed during my visit resulted in increased use of cooling and heating systems powered by natural gas and coal. It is established that carbon emissions from global energy use jumped two per cent in 2018, according to BP’s annual world energy study. The energy sector accounts for two-thirds of all carbon emissions. As temperatures rise, more water will evaporate, but rainfall will remain unpredictable. Countries in the monsoon belt will face more severe droughts in the dry season but could also have to deal with more catastrophic flooding.
Climate change is also playing an increasing role in driving species to extinction. It is reported that up to one million plant and animal species now face extinction owing to habitat destruction and climate change. Climate change is the third biggest driver of biodiversity loss after changes in land and sea use and overexploitation of resources. Global warming even under 20C may cause 5% risk of extinction of animal and plant species. If parts of the country get hotter it will have detrimental effects on hibernating mammals, migratory birds and flowering plants. In addition to these, a staggering 99% of tropical corals are projected to be lost if global average temperature rises by 2?°C, owing to interactions between warming, ocean acidification and pollution. This would be a profound loss of marine biodiversity and human livelihoods.
Coastlines are being reshaped by rising sea levels. In the last decade, sea levels are rising at the fastest rate in 3,000 years at about 3.2 mm per year. In the present scenario, simple physics can explain the cause of sea level rise: a warmer world means a rising sea level. Warm water is less dense than cold, so some of the sea level rise will happen just because the water already in the oceans has begun to expand. Further the melting of continental ice and the retreat of the glaciers increases the sea level rise. The effects of the rise will only slowly become apparent –but may increase to one meter by 2100. With this slow rate, many millions of people living at or a fraction above sea level, and especially to citizens of those countries classed as developing will be in danger. The fatal combination of very high tide and tropical cyclone has hit Bangladesh and the Bengal coast of India many times. High tides and storm surges periodically distort the boundaries between land and sea, making the roads of cities just like canals very often. Also island nations and coastal regions are already feeling the impact. It is also reported that the ice is already shrinking rapidly in the Arctic. Further increase of temperature to 2?°C, the region has a 10–35% chance of becoming largely ice-free in summer.
Indiscriminate abstraction of ground water and overuse of surface water for various purposes may cause severe scarcity of water. This problem will be further aggravated due to global warming. In this situation around 2.3 billion living in the world's water-poor nations could face an even more wretched future. They will see increasingly parched landscapes, empty wells, polluted lakes and rivers that run dry. UN experts calculated that in 2000, people in 30 nations faced water shortages. By 2020, they predict that number will have risen to 50 nations.
According to Intergovernmental Panel on Climate Change (IPCC) report, global CO2 concentrations have increased around 290 ppm since 1880 to 405 ppm in 2016 and 406.55 ppm as of August2018. Without effective climate change mitigation, CO2 concentrations are likely to increase to somewhere between 540 and 1300 ppm in the period 2030 to 2100. Scientists have warned that carbon dioxide levels higher than 450 ppm are likely to lock in catastrophic and irreversible changes in the climate. Around half of the CO2 emitted since 1750 has been in the last 40 years. The global mean temperature increase since the 1850s (currently 0.6 ± 0.2 °C) is estimated to increase by between 1.4 °C and 5.8 °C in 2100
With the rising of global temperature, Aedesaegypti mosquitoes that carry the disease Dengue- the world’s fastest-growing mosquito-borne virus, currently killing some 10,000 people and affecting around 100 million per year could thrive in places that were previously unsuitable for them and benefit from shorter incubation periods. A recent study published in the scientific journal Nature warned that, in a warming world, dengue could spread to the US, higher altitudes in central Mexico, inland Australia and to large coastal cities in eastern China and Japan.
The world’s tropical forests are shrinking at a staggering rate mainly due to deforestation aiming to make way for cattle or agricultural production such as palm oil and soybeans. Deforestation contributes to global carbon emissions because trees naturally capture and lock away carbon as they grow.120, 000 square kilometers of tropical forest were lost in 2018. Some of this loss may be attributed to natural causes such as wildfires Tropical deforestation is now responsible for 11 per cent of the world’s CO2 emissions.
The crop yields are expected to decline by at least 10% in most African Commonwealth countries. The food production in India, Pakistan and Bangladesh will drop mainly due to unpredictable weather pattern as observed in many parts of the countries. When crops fail and starvation threatens, people are forced to fight or flee. Between 50 and 700 million people will be driven from their homes by midcentury as a result of soil degradation alone. The United Nations’ International Panel on Climate Change expects food production to decline by 2% to 6% in each of the coming decades because of land-degradation, droughts, floods and sea-level rise. By 2050, the global population is projected to rise to 9.7 billion, which are more than two billion more people to feed than today.
For climate action, IPCC called for drastic efforts to curb demand for agricultural land, including people shifting towards a plant-based die. Otherwise governments will fall short of their collective goals under the 2015 Paris climate accord, in which nations agreed to limit global warming to no more than 2?°C above pre-industrial levels. Now there is emergent need that researchers must pursue innovative technologies such as carbon capture, implementation of cleaner concept to minimize fossil fuel energy in production process, generation of forest not simply plantation and many more. Overall environmental sustainability requires ambitious political and industrial will, as much as scientific ingenuity.
Now it is established that it has been a terrible news year for climate change. Despite our promises and effort towards zero emission, greenhouse gas emissions have increased by four per cent since the Paris accord was signed in 2015. If it is continued with business as usual and carbon emissions are not drastically reduced by 2030, there will be catastrophic climate change and severe human suffering. Thereby the 2020s will be make-or-break. This is the moment for responding to government stubbornness, whether it’s in the streets in protest, in voting booths or as consumer. Corporate sector are largely responsible for greenhouse gas emissions and their activities are controlled by the demand of individual people. Change of lifestyle and food habit that help to prevent the climate change will obviously change the activities of corporate sectors. Now urgent action is needed, as challenges of 2020, to secure the future of our children and coming generations. No amount of economic cost–benefit analysis is going to help us. We need to change our approach to the climate problem. 
The writer is Former Senior Scientist Central Pollution Control Board