Greenhouse Effect and Climate Change (Part-II)

The Arctic experiences "amplification," where warming is more pronounced than in other parts of the world, says the University of Colorado at Boulder. This is due to a feedback loop where decreasing sea ice and snow cover reduces reflectivity, leading to more absorption of solar radiation and further warming.

The melting of Arctic sea ice and the Greenland ice sheet contributes to sea level rise, impacting coastal areas worldwide. The loss of sea ice also disrupts ecosystems, including those of polar bears and seals.

Thawing permafrost in the Arctic releases stored carbon dioxide and methane, further exacerbating global warming. The Greenland ice sheet is the world's second-largest repository of freshwater, and its melting contributes significantly to sea level rise, with potential for further impact if warming continues.

It will also result in the transformation of 1/6th of the earth's ecosystem and lead to the extinction of 1/4th known species of the earth. If the earth's temperature increases more than 3°C above the pre-industrial level, the terrestrial biosphere will head towards a net carbon source and 1/5th of the ecosystem will get transformed. This will lead to the extinction of 30% of the earth's known species.

The main greenhouse gases whose concentrations are rising are carbon dioxide, methane, nitrous oxide, hydro-chlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and ozone in the lower atmosphere.

Measuring instruments show that water temperatures at the ocean's surface are going up. To some extent, this is a normal pattern: the ocean surface warms as it absorbs sunlight.

The ocean then releases some of its heat into the atmosphere, creating wind and rain clouds. However, as the ocean's surface temperature continues to increase over time, more and more heat is released into the atmosphere.

This additional heat can lead to stronger and more frequent storms like tropical cyclones and hurricanes.

That extra heat is driving regional and seasonal temperature extremes, reducing snow cover and sea ice, intensifying heavy rainfall, and changing habitat ranges for plants and animals-expanding some and shrinking others. As the map below shows, most land areas have warmed faster than most ocean areas, and the Arctic is warming faster than most other regions. In addition, it's clear that the rate of warming over the past few decades is much faster than the average rate since the start of the 20th century.

A wide range of other observations (such as reduced Arctic sea ice extent and increased ocean heat content) and indications from the natural world (such as pole ward shifts of temperature-sensitive species of fish, mammals, insects, etc.) together provide incontrovertible evidence of planetary-scale warming.

Greenhouse gases are atmospheric gases that trap heat from the Earth's surface, contributing to the greenhouse effect. This phenomenon is leading to significant global warming and climate change. The greenhouse effect is primarily caused by the accumulation of greenhouse gases in the Earth's atmosphere, such as carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and water vapor.

These gases trap heat from the sun, preventing it from escaping back into space, leading to a warming greenhouse effect. Human activities like burning fossil fuels (coal, oil, gas), deforestation, and industrial processes significantly increase the concentration of these gases causing greenhouse effect. Natural processes, such as volcanic eruptions and solar radiation, also contribute, but human actions are the dominant drivers of the enhanced greenhouse effect.

Hence food chains in the ocean would be adversely affected and if it is completely destroyed then the density of ocean water would not decrease drastically.

As per IPCC, the sea level is expected to rise from 0.33 m to 0.45m from 1990 to 2100 A.D. Hence statement (1) is correct while (2) is not correct.

The rise in sea level is estimated to be 3 mm per year. At Fiji, its 0.15 meter per year. Hence by 2044, Fiji is likely to be submerged.

In 1920s, Serbian geophysicist and astronomer Milutin Milankovic theorized that variation in eccentricity, axial tilt and precession of the earth's orbit results in cyclical variation in the solar radiation reaching the earth. This orbital forcing influences climatic pattern on earth.

As the ice forms the incremental building of annual layers of snow, lower layers are older than upper and an ice core contains ice formed over a range of years.

The properties of the ice and the recrystallized clarification needed inclusions within the ice can then be used to reconstruct a climatic record over the age range of the core, normally through isotopic analysis.

This enables the reconstruction of local temperature records and the history of atmospheric composition.