Barack Obama's poignant statement, "We are the first generation to feel the impact of climate change and the last generation that can do something about it," underscores the urgency of addressing climate change as an integral facet of our existence. To navigate our environment successfully, one must be attuned to its constituents, encompassing living organisms, as well as factors like temperature, pressure, humidity, and more, which orchestrate a seamless coexistence.
These elements are classified into two categories: biotic and abiotic. Among these, abiotic factors encompass temperature, pressure, humidity, and others, which are intricately interlinked with meteorological processes. These processes, in turn, drive the mechanism of climate change - the profound alteration of average weather conditions spanning decades or more, ushering in shifts towards warmer, wetter, or drier climates. The distinction between climate change and natural weather variability lies in their temporal trajectories, with climate change manifesting as enduring shifts in temperature and climatic patterns.
Climate change is influenced by an array of factors, categorized into two types: human-induced and natural. One paramount phenomenon, global warming, acts as a catalyst for climate change. This has escalated the likelihood of severe and potentially catastrophic transformations in the global environment. Recognizing this, the global community acknowledges the imperative of constraining global warming to 1.5°C and preventing it from exceeding 2°C. Notably, greenhouse gases are pivotal contributors to global warming. Presently, carbon dioxide, methane, and nitrous oxide levels in the Earth's atmosphere surpass levels observed in the past 800,000 years. Human activities emit roughly 30 billion tons of carbon dioxide annually, causing its atmospheric concentration to surge by over 40% since the Industrial Revolution.
Methane concentrations, a byproduct of human activities, surged to more than 2.5 times the pre-industrial levels by the end of the 20th century. Similarly, nitrous oxide concentrations have amplified by around 20% since the onset of the Industrial Revolution. Alongside human influence, natural processes also play a role in shaping this phenomenon, driven by factors such as changes in the Earth's orbit, solar activity variations, shifts in Earth's reflectivity, volcanic activity, and fluctuations in carbon dioxide concentrations.
Historical records reveal that the Earth was approximately 11°F cooler on average in earlier times. While the global temperature saw a marginal rise of 2°F during the prior interglacial period's peak, the advent of activities like deforestation, energy production, and transportation, among others, has augmented the impact of these natural changes.
Deforestation, in particular, presents a profound challenge. Approximately 12 million hectares of forests are engulfed in flames annually, curtailing nature's ability to absorb carbon dioxide. This contributes to a significant portion of global greenhouse gas emissions, alongside factors like agriculture and land use alterations.
The ramifications of global climate change are wide-reaching, bearing a detrimental impact on both the environment and biodiversity. NOAA data highlights that from 1901 to 2020, global temperatures escalated by around 1.8°F (1°C). Meanwhile, sea-level rise, which had maintained a pace of 1.7 mm/year for the majority of the twentieth century, has quickened since 1993. Notably, glaciers have thinned, with the average thickness of 30 well-studied glaciers plummeting by over 60 feet since 1980.
In the Arctic, a 40% decline in summer-end sea ice coverage has been recorded since 1979. Biodiversity loss stems significantly from human land exploitation, especially for agricultural purposes. Over 70% of ice-free land has already undergone transformation due to human activities, jeopardizing the habitat of countless plant and animal species. The intersection of climate change and biodiversity loss is particularly worrisome, with estimates indicating that even a 1.5°C temperature increase could imperil 4% of mammal species. The trajectory becomes graver as temperatures rise, with projections of 8% and 41% endangerment for 2°C and 3°C increments, respectively. Coral reefs, vital ecosystems, are equally vulnerable, facing potential destruction as global temperatures rise.
As global temperatures surge, the ramifications for human health are profound. Climate change ushers in a host of health challenges, from respiratory and cardiovascular disorders to pest-borne illnesses like Lyme disease and West Nile Virus. Water and foodborne diseases, injuries, and fatalities are exacerbated by climate change. Mental health deterioration and an uptick in violent crime have also been associated with changing climatic patterns.
Vulnerability to these health implications hinges on three factors: exposure, sensitivity, and adaptive capacity. The World Health Organization (WHO) notes that climate change is responsible for a minimum of 150,000 annual fatalities, a number projected to quadruple by 2030. Predictably, the toll on human life will amplify, with an anticipated additional 250,000 deaths annually between 2030 and 2050, driven by factors like malnutrition, malaria, diarrhea, and heat stress.
The economic repercussions are dire as well, with projected direct health damage costs ranging from USD 2-4 billion per year by 2030. Health-related expenses compound existing challenges, pushing over 100 million individuals into poverty annually. Bangladesh, for instance, has suffered economic losses amounting to $3.72 billion due to climate change over two decades. A considerable portion of its population grapples with high climate exposure areas.
The rapid disappearance of Himalayan glaciers, expedited by climate change, has unleashed infectious microorganisms into the environment, posing severe health risks. Instances like the 2006 epidemic of Legionnaires' disease in the UK and rising heat-related ailments globally underscore the health perils exacerbated by climate change.
To counteract these dire consequences, global initiatives have been set in motion. The United Nations Framework Convention on Climate Change (UNFCCC) was established in 1992, aiming to stabilize greenhouse gas concentrations in the atmosphere. The subsequent Kyoto Protocol introduced mechanisms like carbon trading and the Clean Development Mechanism, mandating emissions reduction targets for industrialized nations.
The Paris Agreement, a landmark accord approved in 2015, seeks to limit temperature increases to 1.5°C above pre-industrial levels while preventing it from exceeding 2°C. This pact promotes international cooperation on adaptation, financing, and technology sharing, emphasizing nationally determined contributions.
Crucially, local governments and experts must collaborate to spearhead climate change mitigation. Public awareness is paramount, with education and advocacy playing vital roles. Albert Einstein's wisdom resounds: "Those who have the privilege to know have the duty to act." The journey to combat climate change and safeguard the planet's well-being demands collective effort, transcending borders and embracing a shared commitment to a sustainable future.
Probal Talukder is based in Department of Environmental Science and Engineering
Jatiya Kabi Kazi Nazrul Islam University.