IB Biology SL D4.3 Climate change Question Bank

Bottlenose dolphins (Tursiops truncatus) inhabit almost all tropical and temperate oceans between $45^{\circ} \mathrm{N}$ and $45^{\circ} \mathrm{S}$. Over a two-year period, aerial surveys were carried out to investigate the seasonal distribution of these animals along the mid-Atlantic and eastern coastal waters of the USA. Sightings were recorded using a global positioning system (GPS) while flying parallel to the coast approximately 500 m offshore. The diagram below shows a map of the section of coast surveyed. The bar graph shows the seasonal data for summer and winter at the corresponding latitudes ( ${ }^{\circ} \mathrm{N}$ ). A total of 5431 bottlenose dolphins were sighted during these surveys.

Which gas is the main contributor to the greenhouse effect?

Boreal forests stretch across Canada, Russia and Scandinavia. This northern ecosystem accounts for 29 % of the world's forest areas. The long, cold winters favour tall evergreen trees with either needles or scale-like leaves. These trees are wind-pollinated and their seeds are not enclosed in a fruit. The photograph shows a typical boreal forest in winter.

Which activity directly contributes the most to recent increases in atmospheric $\mathrm{CO}_{2}$ concentrations?

Methane is one atmospheric gas that contributes to the greenhouse effect and global warming. What are reasons for this?

I. It absorbs long wave radiation.
II. It is converted to carbon dioxide in the atmosphere.
III. It allows more heat to leave the Earth's atmosphere.

In addition to carbon dioxide, which of these greenhouse gases is the most significant?

The graph shows the mean annual changes in global temperatures between 1880 and 2014. The mean temperature from 1951 to 1980 was used as the value of zero change in temperature.