CO2 Concentration
IB1 Biology HL
Michelle & Sabrina
1. The release of greenhouse gases plays a large role in the development of global warming.
Since the 20th century, there have been significant changes to the climate pattern, due to the
emission of greenhouse gases as a result of human activity. One gas which can be measured
to see the development of such is carbon dioxide. Carbon dioxide, more commonly
recognized as CO2, is a colorless gas found in the atmosphere.
The data below is extracted from that collected in an observatory in Mauna Lao, Hawaii
(19.6ºN, 155.6ºW), on the atmospheric CO2 concentrations (ppm) derived from in situ air
measurements. Data points represent the CO2 concentration in the month of December, with
5 year increments from 1958.
(a) Explain the data in terms of change throughout time and suggest a possible reason for
such a change. (2)
(b) Calculate the percentage change in CO2 concentration from 1958 to 2013. (1)
CO2 Concentration
IB1 Biology HL
Michelle & Sabrina
CO2 concentration (ppm) at different times of the day in La Jolla, California on September
16, 1958, was measured. Data was collected at La Jolla Pier (32.9° N, 117.3° W), at an
elevation of 10m.
*Note: Data points between the time of 10:00 and 15:00 were not recorded in the graph.
(c) State and explain the pattern of the graph by providing potential reasons regarding the
CO2 concentration pattern. (4)
CO2 Concentration
IB1 Biology HL
Michelle & Sabrina
Mark Scheme:
(a) CO2 concentrations gradually increased throughout the years
1988 data point fluctuated, showing a dip in the continuous positive regression
Due to continuous increase in the development of industries
Industries emit CO2
Increase in population
Humans release CO2 through breathing and digesting food
Deforestation
Trees and plants absorb and remove CO2 emission from the air
(b) 26% (
396.82−314.67
314.67
≈ 0.26)
(c) CO2 concentrations are lower during the day and higher at night
Concentration decreases as time reaches the morning and increases as it approaches
nighttime
Plants absorb CO2 during the day, and release CO2 during the evening
No sun in the night to help with the process of photosynthesis
Resulting in the release of CO2
And lower absorption rate