Scientists analyzed the main contributo -rxaaf+aniq; * e3xe.rs to greenhouse gas emissions from human-related actir*;+aa3xixaqene. f-vities. The resulting data is presented in the charts below.

  Which of the followig3ajj (payg 28ng is NOT a greenhouse gas?

1.Outline what is meant by the greenho/g jhqa9 qo6p3b 8hmdyf+z s*+use effect.

2.List two of the main greenhouse gases present in the atmosphere.

  Which characteristics of carbon dioxide make it a greenhxda w81jwt:* jouse gas of concern?

  
The above data obtained from Mauna Loa show trends in atmospheric CO$_2$ concentrations. What conclusions can be made from this graph?
I. There is an annual fluctuation of carbon dioxide concentration in the atmosphere.
II. There is a continuous increase in the average concentration of carbon dioxide in the atmosphere over the years.
III. Increased use of fossil fuels has caused an increase in carbon dioxide in the atmosphere as recorded in Mauna Loa.

  The image shows the observed surface temperature change in the Northe me,jbarns9l16 p2-) ht8vd txrn Hemisphere from 1979 to 2018j9damrs2 ,6e p hlntbv) x1t-9.


1.State the name and source of the greenhouse gas primarily associated with the observed temperature increases.

Name:  

Source:

2.Outline the process through which greenhouse gases increase Earth’s global temperatures.

3.The bar-tailed godwit (Limosa lapponica) nests and breeds on Arctic coasts and tundra and overwinters in the Southern Hemisphere. Predict how the increase in surface temperatures in the Northern Hemisphere may affect the survival of such a migratory bird.

  Which of the following shows tgh71d.i,z p)hgn0wr qhe effect of rising atmospheric carbon dioxide concentrations on mari g17iq, nh).pgr0hwdz ne ecosystems?

  Which statement is not true r 09ub+uf 7cjutegarding greenhouse gases?

  Which of the following k poo+q)hnx5,we-o/ j greenhouse gases is correctly paired with its source?

  Which of the following would x jb.; tv06)kiudu0pqnot delay or decrease the severity of the effects of globald0 uqvu6;.)p ktix j0b warming?

  Scientists have been studying the effects of global warming for some time 20mbmy2loo4z dh97sv i pweq8g.-k+a now, and are worried about the thawing of frozen ice and permafrost in the Arctic region. The imagvb7m y+o09 8qwmka.s -g pl4oeidh2z2e above was taken from a helicopter and shows the crack pattern in permafrost.

Which of the following statements best describes the concerns of scientists?
I. There is frozen organic matter in the Arctic which contains ancient bacteria and viruses
II. With the thawing of ice and organic matter, more carbon dioxide will be released into the air
III. The melting of permafrost in the Arctic will cause the release of methane

  In recent years, climate change has caused serious threats to the hom t2mxyh/ ;1survival of coral reefs. The surface ;y tmx /hm1o2hwaters of the oceans have been monitored for both temperature and salinity values over time. As global mean surface temperatures rose, sea surface salinity patterns have also intensified, with saline areas experiencing increases in salinity and fresher areas experiencing decreases in salinity.

The following table shows the changes in Sea Surface Temperature (SST), Surface Air Temperature (SAT) and Sea Surface Salinity (SSS) from the 1870s to the 1950s and from the 1950s to the present.


1.1.State the period of time when sea surface temperature and salinity changes were the greatest.
The graph shows the Sea Surface Salinity (SSS) changes as compared to Sea Surface Temperature (SST) changes. The wavy line shows the changes in SST, and the dotted line shows the changes in SSS. The average temperatures and sea surface salinity values were set to zero in the period 1950 to 1959.The period from    to   

1.2.Describe the trends seen in the graph for changes in SST and SSS over the time period shown.
The changes in temperatures and salinity caused by climate change have been shown to affect the growth and survival of corals in ocean waters. There have been attempts to grow corals in aquaculture to help understand the threats to corals.

Researchers carried out studies to look at the effects of temperature and salinity on the coral Goniopora columna. Results obtained from these studies might be used to grow and maintain corals on farms.

The corals were reared in seawater and kept in different beakers, in which the temperatures and salinity were varied. At the end of 8 weeks, the specific growth rate (SGR%) was calculated as shown in the equation below. The graph below shows the effect of varying temperature and salinity on the SGR (%).


2.1.State the most suitable temperature for the growth of G.columna.
The most suitable temperature for growth is   $^{circ}C$.

2.2.State the most suitable salinity value for the growth of G. columna.
The most suitable salinity for growth is   psu.
After the experiment, the researchers used a dissecting microscope to examine the tissue residues in the coral skeletons. If no coral tissue was found, the G. columna was assumed to be dead. The survival rate of the coral was calculated using the following formula:


3.1.State the range of salinity that G.columna can survive.
The range of salinity that G. columna can survive is    to    psu
3.2.Deduce the conditions of temperature and salinity that showed a 100% survival rate.

Temperature and salinity changes can increase reactive oxygen in corals, leading to oxidative damage to the coral–zooxanthellae algae symbiotic system. Zooxanthellae algae are expelled during stress caused by climate change which leads to the bleaching of the corals which has been widely observed.

4.Suggest a possible benefit to corals of having photosynthetic symbiotic algae.1
Researchers carried out further experiments to check if adding nutrients to corals being grown in a recirculating filtered seawater system fish tank could counter the effects of bleaching.

Nutrients were added at varying salinity levels between 25 and 40 psu at temperatures of 20, 25 and 30°C for an appropriate period of time. The feed diet contained a mixture of intact and hydrolyzed marine and terrestrial ingredients.

Growth was monitored by measuring the increase in the number of polyps per week for eight weeks. The average increase in polyp number is shown for group Y, which was fed, and group N, which was not fed.


5.1.Calculate the percent increase in growth when nutrients were added to group Y as compared to group N, at 25 °C and 30 psu.
Percentage increase in growth   %
5.2.Comment on the effect of adding nutrients on polyp number at different values of temperature and salinity.

When a coral egg is fertilised by a sperm cell, an embryo is eventually produced which develops into a coral larva called a planula. The planulae float in the ocean for days before dropping to the floor to settle. The planulae prefer to settle on hard coralline algae. Larval settlement is a period in early coral development when they disperse and eventually settle on a substrate.

The researchers studied the developmental phase of coral growth in Briareum violacea species to see if feeding nutrients could encourage larval settlement. After spawning, coral eggs were put into glass tanks and allowed to develop. The ‘larval settlement’ was checked by counting the larvae that were attached to the aquarium tank walls.

The graph below shows the results obtained. Both salinity levels and temperatures have been varied throughout the experiment. Group Y refers to the corals with added nutrients in a recirculating filtered seawater system, and N refers to the corals with no added nutrients.


6.Analyse the effects of adding nutrients on larval settlement and the trend seen with the varying temperatures.

7.Suggest, based on all the data presented, how this research can be used for the growth and maintenance of corals.

  Which of the following statements about methane in thejm0jm/(v nda.n7t5 ue atmosphere are true?
I. Methane is emitted during the extraction of natural gas, coal and oil
II. Methane is released into the atmosphere from cattle farms and other agricultural practices
III. Methane is short-lived in the atmosphere and is converted to carbon dioxide and water

  Scientists predict that global warming k - taw-c(z*0tqk+wkxwill have devastating effects in the future. Which of the followingq0 +w(zwt cx*kakt- -k are the consequences of global warming?
I. Coastal flooding and loss of coastal cities
II. Bleaching of coral reefs
III. Increased spread of tropical diseases

Forest fires occur naturally in various parts of the world and contribute to thqc ;+ ukvt3+ebe health of ecosystems. With an increase in global warming, forest fires have become more frequent. 3ckbte+u +q;v


1.State the name of the process that describes how forest fires are involved in the carbon cycle.

2.Outline how forests can benefit from forest fires.

3.Describe the effects of increased forest fires on the carbon cycle.

The following graphs show the concentration of atmospheric carbon dinqte-. n.fd /(j*a: .yr cbpvsoxide over tpdbc n:. rt yfs.ejn-*. aq(/vime at Mauna Loa Observatory in Hawaii, United States.


1.Describe the overall trend in atmospheric carbon dioxide levels over time.

2.State one factor that has significantly contributed to increases in atmospheric carbon dioxide concentration as seen in the graphs.

3.Explain why the concentration of atmospheric carbon dioxide fluctuates annually.

  Which of the following is NOT a habitat for methanogenic f 85il7ocu .wuarchaeans?

  The image below shows j1a7 a36 an7z6umoafs global sea levels from the years 1880 to 2020.



1.There is a trend line showing changes in sea level from 1920 to 1960 and another trend line showing changes in sea level between 1980 and 2020. Describe the differences in sea level change between these two periods of time.
The increase in sea levels (as shown by the trend lines) is steeper for the years from    to    compared to the years from 1920 to 1960.
2.Outline the reasons for linking atmospheric carbon dioxide levels to the rise in sea levels.

Ecosystems growing in salt marshes are able to help reduce the effects of climate change by the sequestration (capture) of carbon. Sea level rise (SLR) has affected these ecosystems by flooding and eroding coastal areas.

The results from a recent study modelling the effects of a one-metre sea level rise on carbon sequestration by salt marshes in New York, United States, are shown in the graph below. The data shows the predicted effects by the year 2100.

3.Suggest an explanation for the difference in carbon sequestration between no SLR and one meter SLR, shown in the prediction graph.

4.Draw a diagram of the carbon cycle for a terrestrial ecosystem, and include carbon sinks, and processes associated with the cycle.

1.Describe the method used by scientists to deduce carbon dioxide con,sh xk frt-)*n-+)v u f:ere:7idnjqvcentrations from thousands of years au:+hrt :nr- -vedi x*fve s)jqkfn7),go.

2.Explain why rising levels of atmospheric carbon dioxide are the main cause of climate change.

3.How have increased carbon dioxide levels affected reef-building corals in marine waters?

  Mesocosms were used to study the response of freshwater snails and w+ qgzzjf; 7w 4t1xi*9q h7fbjep;)qlalgae to warming in two different systems, one with fish present and one without fish. 7j 9xfw;ftw4;7 +lzqiq*zhjbpq)g 1 eEach mesocosm had the following added to it: two different species of snails Bellamya sp. and Radix sp., and the same (one) species of phytoplankton. The snails feed on phytoplankton and are in turn preyed upon by the fish.

The following diagrams show the mesocosms used for the study. C is the control without fish at environmental temperature and F is the control with fish at environmental temperature. W is the mesocosm at increased (+4.5 °C) temperature without fish, and WF is the mesocosm at increased temperature with fish. The temperature increase of +4.5 °C was chosen to simulate the possible environmental warming that could happen in this region by the end of the century.


1.State two other variables, other than those given, that need to be controlled in the mesocosms.2


The following graphs show the fluctuations in the density of the two snails against the period of time (x axis) the study took place, along with the treatments.
(C - control, W - warming , F - with fish , WF - warming with fish)


2.Draw a line in graph A to show the peak density value for both the control (C) and warming (W) for the snail Bellamya sp., as shown in graph B for the snail Radix sp.

3.Compare and contrast the effects of warming on each species of snails in the mesocosms (W and WF).

4.State which is the preferred snail for consumption by the fish.
The preferred snail for consumption by the fish is the   .
5.Predict the effect of warming in the presence of fish on the biodiversity (of snails) in open ecosystems.


6.The density of phytoplankton, shown in the graph above, was seen to vary in the presence of the fish. Suggest a reason for the increase in phytoplankton density shown in the warmer mesocosm containing fish.

7.Mesocosms have been used to simulate conditions for climate change and other studies. Outline an advantage and a disadvantage of using mesocosms to carry out these investigations.

  Climate change can impb-xy 1b ypr;.b:t4owk+ljr2 qact which of the following events?
I. Growth of Cerastium arcticum (Arctic mouse-ear chickweed)
II. The arrival of migrating Rangifer tarandus (reindeer)
III. The mating of Parus major (great tit)

1.Compare the concentration and potency of carbon dioxidebxp(9gkt6tfld5.- yz and methane as greenhouse gases in the ax ( k6tb.gd9t5-pf lyztmosphere.

2.Explain the reasoning of climate scientists for identifying human activity as the main cause of climate change.

3.Discuss the consequences of global warming with reference to the climate, marine organisms, and changes to coastal regions and Arctic ecosystems.

  Which of the following are triggered by ph/s:e2ny9r+3 mcnsn jt9 jgk /fotoperiod?

I. Bird migration
II. Bird nesting
III. Hatching of eggs

  Which of the following is an example of evolution due tk 8jokw7 zmimd-(;8 weo climate change?