Some Key Points
- This is the key climate metric, it is measured relative to the average global land/ocean temperature between 1951 and 1980.
- It is the average Global Land/Ocean Temperature Deviation.
- It is close now to 1oC above that average.
- The UN warns that to avoid real issues for our habitat we should not go above 1.5oC and that above 2oC humanity will move into uncharted and dangerous territory.
- Climate change is normally quite natural, but the rate of change today is caused by man made greenhouse gas emissions, mainly carbon dioxide (CO2) from burning fossil fuels.
- In the past 10 years global CO2 emissions increased by 16%, with ever increasing fossil fuel use.
- The high/low projections to 2040 simply follows this trend in CO2 emissions, it is the nothing changes scenario.
- We see no real sign that the world will react rapidly enough to stop this, there just isn't the political will, by 2040 we will be at least 2oC warmer than the pre 1980 period.
There are many sources of global temperature deviation data and they all tell the same story, the planet is warming up. The cause of the warming is the increase in the concentration of greenhouse gasses in the atmosphere, which prevent heat from radiating away from the planet into space.
Figure 6.1 shows the increase in temperature from 1880 to 2017 the temperature has increased by about 1.25oC. However global warming is defined* as the increase in temperature fron the global average between 1951 and 1980 and it now stands at +0.9oC.
Figure 6.2 shows the average worldwide land/ocean temperature together with the data from the northern and southern hemispheres. Warming is clearly greater in the north where most of the planet lives, where there is most industry and where the greenhouse gas emissions are the greatest.