\(\mathrm{CO}_{2}\) is not a poisonous gas but there is increase in concentration of \(\mathrm{CO}_{2}\) in the atmosphere due to burning of fossil fuels and decomposition of limestone. The increase in concentration of \(\mathrm{CO}_{2}\) may lead to (a) increase in photosynthesis in plants (b) higher concentration of \(\mathrm{CO}_{2}\) in water (c) increase in greenhouse effect, thus raising the temperature (d) increase in formation of metal carbonates.

Photosynthesis is the miraculous process by which plants, algae, and some bacteria convert carbon dioxide (CO2), water, and sunlight into sugars and oxygen. This cornerstone of life allows plants to create their own food and is crucial for the survival of almost all living organisms on Earth.

With the increased atmospheric CO2 levels due to human activities, notably the burning of fossil fuels, plants have access to more of the raw material required for photosynthesis. In essence, more CO2 could potentially lead to an increase in photosynthesis, accelerating plant growth. This is sometimes referred to as 'CO2 fertilization.' However, this benefit is limited, for plants also need adequate amounts of water, light, and nutrients. Once those are maxed out, additional CO2 won't boost photosynthesis and can even harm plant life in other ways.

The greenhouse effect is a natural phenomenon that keeps our planet warm enough to sustain life. Greenhouse gases, such as CO2, methane, and water vapor trap heat in the Earth's atmosphere and prevent it from escaping into space. While this is necessary for our survival, human activities have led to increased levels of these gases, particularly CO2, causing the greenhouse effect to intensify.

An intensification of the greenhouse effect can lead to global warming, which is already causing a host of environmental issues. The impacts include melting polar ice, rising sea levels, more extreme weather events, and shifts in wildlife populations and habitats. Reducing CO2 emissions is therefore critical to mitigating the worst impacts of climate change.

The carbon cycle represents the movement of carbon through the Earth's atmosphere, oceans, soil, plants, and animals. Carbon is the building block of life and circulates through this cycle via processes such as photosynthesis, respiration, and decay. Humans have significantly altered the carbon cycle, primarily through the burning of fossil fuels and deforestation, adding more CO2 into the atmosphere than the cycle can naturally process.

This addition of CO2 upsets the balance of the carbon cycle, leading to increased atmospheric and oceanic CO2 levels. Actions such as reforestation, protecting existing forests, and adopting low-carbon technologies can help restore this crucial balance.

As CO2 concentrations in the atmosphere rise, more of the gas dissolves in the Earth's bodies of water, including oceans, lakes, and rivers, a process described by Henry's Law. This alters the chemistry of the water through a process called ocean acidification, where CO2 reacts with seawater to form carbonic acid.

The increase in aquatic CO2 concentration can harm marine life, particularly organisms with calcium carbonate shells or skeletons, such as coral, oysters, and some plankton species. These effects, in turn, can disrupt entire marine ecosystems and the communities that rely on them. Efforts to monitor and reduce atmospheric CO2 levels are crucial in preventing further harm to aquatic systems.