Reducing our CO2 emissions

Carbon Capture and Storage (CCS) is only one tool available for reducing greenhouse gas emissions. The easiest and fastest approach is to use less fuel through conservation and efficiency. Renewables such as geothermal, hydro and wind are also important, particularly for New Zealand. Substituting gas for coal in power stations (an example of “fuel switching”) can halve emissions, even without CCS, and has helped the USA to recently reduce their national emissions. Many methods will be needed in concert to help reduce global warming. Man-made emissions must be reduced drastically over the next few years if we want to reduce the risk of having extreme climates and large rises in sea level.

Ways we can try to reduce future emissions

In the diagram to the right, the top of the orange wedge marks the level of a widely used scenario of expected global man-made CO2 emissions through to 2050; the bottom of the green wedge show the level needed if we are to limit global warming to only 2° by 2100. The colours in-between denote the hoped-for proportions of the six main options we can use to reduce emissions to the required level, while still meeting likely energy demands. All options will be needed if we are to succeed.

Natural CO2 systems

Natural emissions from volcanoes, and seeps throughout New Zealand, emit CO2 that we cannot reasonably do anything about. Two examples of CO2-rich natural systems in New Zealand are shown below:

CO2 seep at Kongahu, West Coast.

CO2 seep at Kongahu, West Coast. Photo: Rupert Sutherland, GNS Science

CO2 bubbling up at Lake Rotomahana.

CO2 bubbling up at Lake Rotomahana. Photo: Julian Thomson, GNS Science.