Greenhouse Effect and Global Warming Questions in English

(C) The $Greenhouse \text{ } effect$ is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases. This process maintains the Earth's temperature at a level suitable for life. However, an increase in the concentration of greenhouse gases leads to global warming.

(A) The greenhouse effect is a naturally occurring phenomenon that is responsible for heating of Earth's surface and atmosphere.
Without the greenhouse effect,the average temperature at the surface of the Earth would have been $-18^{\circ}C$ rather than the present average of $15^{\circ}C$.
Therefore,$i = 15^{\circ}C$ and $ii = -18^{\circ}C$.

(B) The relative contribution of various greenhouse gases to global warming is as follows:
$1$. Carbon dioxide $(CO_2)$: $60\%$
$2$. Methane $(CH_4)$: $20\%$
$3$. Chlorofluorocarbons $(CFCs)$: $14\%$
$4$. Nitrous oxide $(N_2O)$: $6\%$
Therefore,the correct order of contribution is $CO_2 > CH_4 > CFCs > N_2O$.

(D) Greenhouse gases are gases in the atmosphere that trap heat and contribute to the greenhouse effect.
Major greenhouse gases include carbon dioxide $(CO_2)$,methane $(CH_4)$,chlorofluorocarbons $(CFCs)$,and nitrous oxide $(N_2O)$.
Oxygen $(O_2)$ is the primary gas required for respiration and is not a greenhouse gas because it does not absorb infrared radiation.
Therefore,the correct option is $D$.

(C) The El Niño effect is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean. It is a significant phenomenon associated with global climate change and is closely linked to the broader context of global warming. While it is a natural cycle,its intensity and frequency are influenced by the rising global temperatures.

(C) Greenhouse gases are responsible for the greenhouse effect,which leads to an increase in the Earth's atmospheric temperature.
Major greenhouse gases include carbon dioxide $(CO_{2})$,methane $(CH_{4})$,nitrous oxide $(N_{2}O)$,and chlorofluorocarbons $(CFCs)$.
Among the given options,$CH_{4}, CO_{2},$ and $N_{2}O$ are the primary greenhouse gases that contribute significantly to global warming.

(B) The gases responsible for the greenhouse effect are $CO_2, CH_4, N_2O, CFCs$,etc.
Earth's atmosphere,with a high concentration of greenhouse gases,is transparent to incoming short-wave solar radiation but absorbs outgoing long-wave infrared radiation,particularly Earth's thermal radiation (heat rays).
This process traps heat near the Earth's surface.
In this way,the Earth's atmosphere functions similarly to a greenhouse by warming the interior.

(D) Oxygen $(O_2)$ is not a greenhouse gas because it does not absorb infrared radiation.
Greenhouse gases are gases that trap heat in the atmosphere,contributing to the greenhouse effect.
The primary greenhouse gases include carbon dioxide $(CO_2)$,methane $(CH_4)$,chlorofluorocarbons $(CFCs)$,nitrous oxide $(N_2O)$,and water vapour $(H_2O)$.

(A) The greenhouse effect is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere,some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases,atmospheric dust,and water vapors. This re-radiated heat is trapped in the atmosphere,keeping the Earth warm enough to sustain life. Therefore,the trapping of re-radiated heat by atmospheric components is called the greenhouse effect.

(C) The greenhouse effect refers to the selective energy absorption by greenhouse gases (e.g.,$CO_2$,$CH_4$,$N_2O$,$CFCs$,and water vapour) in the atmosphere. These gases allow short-wavelength solar radiation to pass through but absorb long-wavelength infrared radiation (heat) and reflect it back to the Earth's surface. Nitrogen $(N_2)$ is not a greenhouse gas as it does not absorb infrared radiation.

(A) $El\; Nino$ effect is a complex weather pattern resulting from variations in ocean temperatures in the Equatorial Pacific. It is closely associated with global warming because the rise in global temperatures exacerbates the frequency and intensity of these climatic anomalies. These changes lead to significant environmental disruptions and unpredictable weather patterns worldwide.

(C) $CO_2$ is a greenhouse gas that is opaque to infra-red (thermal) radiation.
It allows short-wave solar radiation to enter the atmosphere but traps the long-wave infra-red radiation emitted by the Earth's surface.
This prevents the heat from escaping back into space,thereby increasing the greenhouse effect and leading to global warming.

(B) Global warming refers to the gradual increase in the Earth's average temperature due to the greenhouse effect.
Consequences of global warming include rising sea levels due to melting polar ice caps,increased frequency and intensity of extreme weather events like storms,and adverse effects on human health due to heat stress and the spread of vector-borne diseases.
However,global warming does not lead to increased agricultural productivity worldwide. In fact,it often leads to decreased productivity in many regions due to unpredictable weather patterns,droughts,and soil degradation.
Therefore,the correct option is $(B)$.

(B) The greenhouse effect is a natural process that warms the Earth's surface.
When the Sun's energy reaches the Earth's atmosphere,some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases.
Without this natural greenhouse effect,the heat would escape into space,and the Earth's average surface temperature would be approximately $-18^{\circ} C$,rather than the current average of $15^{\circ} C$.

(C) Greenhouse gases are gases that are transparent to incoming solar radiation but trap and partially reflect back long-wave heat radiation,specifically infrared radiation,which leads to the greenhouse effect.
These gases include $CO_{2}, CH_{4}, CFCs, N_{2}O, O_{3}$,and water vapor.

(B) According to the $NCERT$ textbook,the relative contribution of various greenhouse gases to total global warming is as follows:
$1$. Carbon dioxide $(CO_{2})$: $60\%$
$2$. Methane $(CH_{4})$: $20\%$
$3$. Chlorofluorocarbons $(CFCs)$: $14\%$
$4$. Nitrous oxide $(N_{2}O)$: $6\%$
By observing the given pie diagram:
$A$ corresponds to $60\%$,which is $CO_{2}$.
$B$ corresponds to $20\%$,which is $CH_{4}$.
$C$ corresponds to $14\%$,which is $CFCs$.
$D$ corresponds to $6\%$,which is $N_{2}O$.
Therefore,the correct identification is $A - CO_{2}, B - CH_{4}, C - CFCs, D - N_{2}O$.

(D) The atmosphere surrounding the earth acts like the glass walls of a greenhouse. It allows incoming solar radiation to pass through but prevents the long-wave infrared radiation emitted by the earth's surface from escaping into space.
Thus,the atmosphere acts as a greenhouse,trapping heat. The gases in the atmosphere most responsible for keeping the earth's surface warm are $CO_{2}, CH_{4}, CFCs, N_{2}O$,and water vapor.
Statement $I$ is correct because greenhouse gases absorb infrared radiation and re-emit it towards the earth,causing heating.
Statement $II$ is correct as $CO_{2}, CH_{4}, CFCs$,and $N_{2}O$ are the primary greenhouse gases.
Statement $III$ is correct because an increase in the concentration of these gases leads to an increase in the mean global temperature,a phenomenon known as global warming.
Therefore,all three statements are correct.

(C) Global warming leads to the melting of glaciers and the loss of cold-climate habitats. The $Snow leopard$ is an organism specifically adapted to high-altitude, cold mountain environments. As temperatures rise, their habitat shrinks, forcing them to move to higher altitudes until they have nowhere left to go, making them highly vulnerable to extinction compared to the other listed organisms.

(D) Global warming is the increase in the average temperature of the Earth's atmosphere.
Its major consequences include:
$1$. $El$ $Nino$ effect: Changes in ocean temperatures affect global weather patterns.
$2$. Shifting of climatic zones: As temperatures rise,species and ecosystems shift towards higher latitudes or altitudes.
$3$. Rise in sea level: Melting of polar ice caps and thermal expansion of seawater lead to a rise in sea levels.
Therefore,the correct set is $(a, c, g)$.

(A) Greenhouse gases are responsible for the greenhouse effect.
They are transparent to incoming solar radiation (short-wave) but act as absorbers of long-wave infrared radiations emitted from the earth's surface.
This trapped heat prevents the earth from cooling down,leading to global warming.

(N/A) The greenhouse effect is a naturally occurring phenomenon that is responsible for heating the Earth's surface and atmosphere due to an increase in the concentration of greenhouse gases like carbon dioxide and methane.
Clouds and gases reflect about one-fourth of the incoming solar radiation and absorb some of it,but almost half of the incoming solar radiation falls on the Earth's surface,heating it,while a small proportion is reflected back.
The surface of the Earth re-emits heat in the form of infrared radiation,but part of this is not reflected back into space due to greenhouse gases,which leads to the heating of the Earth's atmosphere.
Global warming is the gradual increase in the Earth's average temperature caused by the enhanced greenhouse effect.
Scientists believe that this rise in temperature is leading to harmful changes in the environment and resulting in odd climatic changes (e.g.,$El$ $Nino$ effect),thus leading to increased melting of polar ice caps and glaciers.
Global warming can be controlled by: $(a)$ Cutting down the use of fossil fuels,$(b)$ Improving the efficiency of energy usage,$(c)$ Reducing deforestation,$(d)$ Planting trees,and $(e)$ Slowing down the growth of the human population.

(N/A) Global warming is primarily caused by the increase in the concentration of greenhouse gases in the atmosphere,which trap heat. The relative contributions of these gases to total global warming are as follows:
$1$. Carbon dioxide $(CO_2)$: It is the most significant contributor,accounting for $60\%$ of the total global warming.
$2$. Methane $(CH_4)$: It contributes $20\%$ to the total global warming.
$3$. Chlorofluorocarbons $(CFCs)$: These contribute $14\%$ to the total global warming.
$4$. Nitrous oxide $(N_2O)$: It contributes $6\%$ to the total global warming.
These percentages illustrate that $CO_2$ is the primary driver of the greenhouse effect,followed by methane,$CFCs$,and $N_2O$.

(D) The figure illustrates the greenhouse effect.
$P$ represents the incoming solar radiation from the Sun,which includes visible light and other short-wave radiations that pass through the atmosphere to reach the Earth's surface.
These radiations are absorbed by the Earth's surface and then re-emitted as long-wave infrared radiations,which are trapped by greenhouse gases.
In the context of standard $NCERT$ diagrams for the greenhouse effect,the incoming solar radiation is typically represented as visible light or short-wave radiation.

(A) The greenhouse effect is a natural process that warms the Earth's surface.
Without the greenhouse effect,the Earth's atmosphere would not trap heat,leading to a much colder planet.
The current average temperature of the Earth's surface is approximately $15^{\circ}\,C$.
If the greenhouse effect were absent,the average temperature of the Earth's surface would drop to approximately $-18^{\circ}\,C$.
Therefore,$P = 15^{\circ}\,C$ and $Q = -18^{\circ}\,C$.

(C) The Earth's surface is heated primarily by solar radiation.
Solar energy reaches the Earth in the form of electromagnetic radiation,which includes ultraviolet,visible,and infrared rays.
While the atmosphere absorbs some of these,the Earth's surface absorbs the incoming short-wave solar radiation and re-emits it as long-wave infrared radiation.
However,the direct heating of the Earth's surface is most significantly associated with the absorption of infrared radiation,which is responsible for the greenhouse effect and maintaining the Earth's temperature.

(C) According to the $NCERT$ textbook data on the relative contribution of greenhouse gases to global warming:
$1$. Carbon dioxide $(CO_2)$ contributes $60\%$ to global warming, which corresponds to $R$.
$2$. Methane $(CH_4)$ contributes $20\%$ to global warming, which corresponds to $Q$.
$3$. Chlorofluorocarbons $(CFCs)$ contribute $14\%$ to global warming, which corresponds to $P$.
$4$. Nitrous oxide $(N_2O)$ contributes $6\%$ to global warming.
Therefore, $P = CFCs$, $Q = \text{Methane}$, and $R = \text{Carbon dioxide}$.

(A) According to the $NCERT$ textbook,the global temperature of the Earth has increased by $0.6^{\circ}C$ during the past century. This rise in temperature is primarily attributed to the increase in greenhouse gases in the atmosphere,leading to global warming.

(B) Greenhouse gases like $CO_2, CH_4, CFCs$,and $N_2O$ are responsible for the greenhouse effect.
These gases have the property of absorbing long-wave infrared radiation (heat) that is reflected back from the Earth's surface.
By trapping this heat in the atmosphere,they prevent it from escaping into space,which leads to an increase in the Earth's average temperature,a phenomenon known as global warming.
Therefore,the correct option is $B$.

(D) The greenhouse effect leads to global warming,which causes several environmental changes:
$1$. Increased global temperatures lead to the melting of polar ice caps and glaciers,including the Himalayan snow caps.
$2$. As ice melts and water expands due to heat,the sea level rises,threatening to submerge low-lying coastal regions.
$3$. Changes in global temperature patterns can alter climate cycles,including the occurrence of the El Niño effect.
Therefore,all the mentioned options are consequences of the greenhouse effect.

(D) Global warming refers to the gradual increase in the Earth's average temperature due to the greenhouse effect.
$1$. Melting of glaciers: Increased temperatures cause polar ice caps and glaciers to melt,leading to a rise in sea levels.
$2$. Change in rainfall pattern: Global warming alters atmospheric circulation,leading to unpredictable and extreme weather events,including changes in rainfall patterns.
$3$. Increase in sea level: As glaciers melt and ocean water expands due to heat,sea levels rise.
$4$. Increase in crop production: Global warming generally has a negative impact on agriculture. Increased heat,drought,and unpredictable weather patterns typically lead to a decrease,not an increase,in crop production in many regions. Therefore,an increase in crop production is not a consequence of global warming.