CONTEXT

• Climate change is considered the most significant existential threat of our lifetimes, posing grave risks to human civilization, ecosystems, and the planet’s overall stability
• Gases, including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases, act like a blanket in the atmosphere, trapping heat from the sun and preventing it from escaping back into space.
• The increase in concentrations of GHGs leads to a phenomenon known as global warming, where more heat is trapped in the Earth’s atmosphere. This results in a gradual rise in the average temperature of the planet over time.
• Unlike short-term weather events, such as a cold spell or a hot day in a specific region, global warming refers to the sustained increase in average temperatures across the entire planet. It is a gradual and ongoing process with far-reaching consequences for ecosystems, weather patterns, sea levels, and human societies worldwide

GREEN HOUSE GAS EFFECT

• The primary greenhouse gases (GHGs) ranked by their damage potential are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). While methane and nitrous oxide are more potent heat-trappers molecule-for-molecule compared to carbon dioxide, their lower concentrations mitigate some of their impact.
• Over the past 800,000 years, carbon dioxide concentrations ranged between 180 and 280 parts per million (ppm). However, in the last century, these levels have surged to around 420 ppm due to human activities such as fossil fuel combustion.
• The combustion of fossil fuels, driven by humanity’s energy demands, is the primary contributor to GHG emissions. This activity far surpasses other sources like agriculture and waste in terms of emission volume.
• Annually, human activities emit a staggering 59 billion tons of GHGs, overwhelming the capacity of natural systems like oceans and land to absorb these gases. This leads to a buildup of GHGs in the atmosphere, intensifying the greenhouse effect and resulting in higher global temperatures.
• The Earth has already warmed by 1.2 degrees Celsius, with particularly pronounced warming observed in oceans and higher latitudes. This warming trend is a direct consequence of increased GHG concentrations in the atmosphere.
• Climate change affects every corner of the globe; there is no region untouched by its consequences, from altered weather patterns to ecosystem disruptions.
• Climate impacts are expected to worsen before improving. However, proactive measures can still be taken to mitigate risks and reduce the severity of climate-related challenges.

INDIAN CITIES

• In 2023, fifteen cities across India encountered five or more days of extreme heat waves, while twelve cities saw over 100 days of temperatures exceeding the average. This trend highlights the increasing frequency and intensity of heat-related events in the region.
• The warming of oceans contributes to the melting of ice caps and the expansion of ocean water, leading to rising sea levels globally. This phenomenon poses a significant threat to coastal cities and regions, exacerbating the risk of inundation and flooding.
• Vulnerable Indian Cities: Among Indian cities, Mumbai, Cochin, Bhavnagar, Vishakhapatnam, Mangaluru, and Chennai are identified as the most susceptible to inundation in the coming decades due to rising sea levels. These cities face heightened risks of coastal flooding and other climate-related hazards.
• The projections indicate that these cities are likely to experience increased inundation and coastal vulnerability over the course of this century, emphasizing the urgent need for adaptation and mitigation measures to address climate change impacts.

OTHER CHALLENGES

• Increased Moisture in Warmer Air: Warmer air has the capacity to hold more moisture, resulting in a higher frequency and severity of extreme weather events such as bomb cyclones, storms, floods, and droughts. These events can cause significant damage to infrastructure, agriculture, and ecosystems, leading to economic losses and human displacement.
• Ocean Acidification from CO2 Absorption: The absorption of excess carbon dioxide by oceans leads to acidification, which has detrimental effects on marine life. Coral reefs, vital ecosystems, are bleached and degraded, while other marine habitats suffer destruction. This poses a threat to marine biodiversity and the livelihoods of coastal communities dependent on these ecosystems.
• Species Migration and Biodiversity Loss: Rising temperatures and changing habitats force many species to migrate to higher latitudes or altitudes. This migration exposes them to new predators, diseases, and environmental stressors, leading to species extinction and a loss of biodiversity. The disruption of ecosystems has far-reaching consequences for ecosystem services and human well-being.
• Human Impacts: Climate change-induced events like crop failures, forest fires, climate migration, emergence of new disease vectors, and the loss of fishing livelihoods have profound impacts on human populations. These events can lead to food insecurity, displacement, economic hardship, and increased vulnerability to health risks, exacerbating existing social inequalities and challenges
• Tipping Points: Tipping points are natural phenomena characterized by runaway positive feedback loops. An example is the melting of ice caps exposing darker earth, which absorbs more heat, causing further ice melt and amplifying warming. Such tipping points can lead to catastrophic consequences, including accelerated sea-level rise and temperature increases.

WAY FORWARD

• Climate scientists emphasize the critical need to limit global warming to 1.5 degrees Celsius to mitigate the most severe impacts of climate change. Beyond this threshold, well-known consequences like sea-level rise worsen, and the risk of triggering irreversible “tipping points” in Earth’s systems increases significantly.
•  Achieving net zero emissions is crucial in the fight against climate change. This involves reducing GHG emissions as much as possible and offsetting remaining emissions through activities like reforestation and carbon capture.
•  Climate researchers have determined a precise global carbon budget of 280 billion tons of GHGs to limit warming to 1.5 degrees Celsius. This budget acts like a financial budget, where emissions are tallied each year until reaching net zero, ensuring we do not exceed our limit.
• Urgent Action Needed: Current emission rates indicate that we will surpass our carbon budget before 2030. To stay within the 1.5°C limit, global emissions must be cut in half by 2030 and reach zero by 2040. While some countries aim for net zero by 2050 or later, more ambitious timelines are necessary to avert the worst impacts of climate change.
• India’s Target: India’s target of reaching net zero by 2070 falls short of the urgency required. A concerted effort is needed to accelerate this timeline, aiming for net zero emissions as close to 2040 as possible to align with global climate goals and safeguard against catastrophic climate outcomes.