Practise IB Biology HL D4.3 with climate data questions on greenhouse forcing, feedback, ocean acidification, habitat shifts, phenology and carbon sequestration.
Average human internal (core) body temperature is , with slight variations between day and night. The average surface temperature of the Earth in the 20th century was . It has now risen to .
Explain how the burning of fossil fuels has contributed to the increase in the Earth's temperature.
Melting polar ice due to global warming is reducing reflection of sunlight from the Earth. Identify with a reason whether this will result in positive or negative feedback.
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.
In some areas there are gaps in the boreal forest where trees fail to grow and peat tends to accumulate. Suggest reasons for this.
An increase in global temperatures poses a critical threat to boreal forests. Explain the consequences of climate change to this northern ecosystem.