What will Global Warming lead to?

As explained in “What is Global Warming", an increase in average atmospheric temperatures does not mean equal increases in temperature in every region worldwide, but actually varied increases for different regions. The general trend would be that regions farther away from the equator would experience more significant changes than regions nearer to the equator.

In natural ecosystems, unmanaged land ecosystems, such as forests, would experience the greatest impact. Plant species would have to adapt to the changes through migration. In mid-latitudes (30 to 60 degrees), if the temperature were to increase between 1^oC and 3.5^oC in the next 50 years, climate regimes would shift poleward by 150-155km. Trees species have migration rates in the range of 4-200km/100 years^[14]. Many parts of the ecosystem will become incompatible with the new climate there, making the area more vulnerable to diseases, insects and fire. Plant species will react differently to such changes, therefore compositions of ecosystems will also change.

Figure 4.1
Arctic Sea Ice in 1979 and 2005.

Other effects to natural ecosystems would be a shortened period of time that ice covers the land, increasing the time for biological activity. Ice shelves, particularly from Greenland and Antarctica, would melt and raise global sea levels. Ice shelves have already melted a significant amount in the last few decades (Figure 4.1). In summers, lake waters will have increased problems with anoxic (water with no dissolved oxygen) conditions^[15]. Fish distribution will change; cold water species
will lose habitat whereas warm water species will gain. Permafrost melting will damage the foundations of the soil, altering the
way plants grow and any structures that have been built on this foundation. Wildlife species would migrate to adapt to their own needs and migration rates are unpredictable, which can damage ecosystems^[16].

The agricultural ecosystem have a stimulated crop growth and yield due to increased CO₂ levels and warmer temperatures. The growth season is longer and more areas farther north can support growth of crops. These benefits could however be offset by insufficient soil nutrients, air pollution and increased radiation, as well as a lack of water availability, extreme heat and droughts^[17]. Tropic agricultural regions are very sensitive to changes in temperate and precipitation. Any increased rainfall would increase the risk of erosion and floods, adding to the degrading agricultural soil and water quality. Farm management techniques will need to be adapted to
respond to changes.