The recent findings of a report titled “Trajectories of the Earth System in the Anthropocene” have raised serious concerns about global warming and its potential impact on the earth’s natural equilibrium. Global temperatures are currently around 1°C above pre-industrial levels and rising at a steady rate of 0.17°C per decade. The study predicts that if temperatures surpass 2°C above pre-industrial levels, a not-so-ideal situation called a “hothouse” effect could occur, resulting in drastic climatic changes with potential to make parts of Earth uninhabitable.
Risks of “Hothouse” conditions
A “hothouse” condition is characterized by global temperatures being 4-5 degrees higher than the pre-industrial level. Alarmingly, the sea levels may rise up to 60 metres more than they are today even if countries meet their emission reduction goals under the Paris climate agreement. This means, certain low-lying areas could become entirely submerged leading to massive displacement of people and ecological damage.
The Role of Feedback Processes
Temperature on Earth is determined not only by human emissions of greenhouse gases but also by several natural systems called “feedback processes”. Scientists have studied 10 such systems which include permafrost, methane hydrates trapped in ocean floors, land and ocean carbon sinks, Arctic summer sea ice, Antarctic sea ice, polar ice sheets among others. These systems help in maintaining the carbon balance and thus temperature on Earth. However, if one system fails and starts releasing excessive CO2 into the atmosphere, it could possibly trigger a domino effect causing other systems to collapse too.
Understanding Natural Systems
Permafrost refers to soil that remains frozen for at least two consecutive years, typically found in Earth’s higher latitudes. Methane hydrate is a lattice of ice trapping methane molecules, usually found beneath the Arctic permafrost and ocean floors. Carbon sinks are reservoirs for carbon or carbon compounds like CO2. They can be natural, such as plants, soil, oceans, or man-made like landfills and carbon-capture storage processes.
Regions Impacted
The Sahel region of Africa is a semi-arid belt marking the geographical and cultural transition between the African continent’s fertile tropical regions and the arid Sahara desert to the north. Changes to climate patterns could heavily impact this already ecologically sensitive zone. The boreal forest, also known as taiga, stretches across North America and Eurasia and is susceptible to changes in temperature.
Climate Phenomena
Deep-ocean currents, controlled by temperature and salinity of the water, known as thermohaline circulation, also influence climate. El Nino Southern Oscillation (ENSO) is another important climate phenomenon characterized by warming (El Nino), cooling (La Nina) and neutral states of the ocean surface in the central and eastern tropical Pacific Ocean.
Societal Impact of the Hothouse Earth Period
A shift into a Hothouse Earth period could push global temperatures to levels not seen in the past 1.2 million years. While immediate impacts may not be apparent, once triggered, the shift would be irreversible. Though recent extreme weather events globally cannot be definitively linked to a potential 2°C rise, it is a worrying indicator of Earth becoming more sensitive to warming.
Possible Solutions
The hothouse scenario can potentially be avoided if humans fundamentally re-adjust their relationship with the planet. This requires a reorientation in human values, behavior, and technologies. Along with curbing fossil fuel usage by mid-century, mitigation measures like tree planting, forest protection, development of carbon sequestration technologies should also be pursued on a massive scale. Enhancing biological carbon stores through improved forest and agricultural management, biodiversity conservation, and underground CO2 storage could be part of the solution. However, the advent of the Anthropocene era, where human activity directly affects the planet, requires a larger conversation about our responsibility towards Earth.
