Reducing emissions of greenhouse gases

There is now widespread agreement that global warming can be mitigated by reducing emissions of greenhouse gases, as a matter of urgency

As described above (, there is no longer any doubt about the connection between man-made emissions and global warming.  There is now international agreement on the need for action to mitigate, or reduce, human impact on the climate by swiftly reaching ‘net zero’ emissions to avoid further increases in global temperature.

New research findings, by the Intergovernmental Panel on Climate Change (IPCC), have suggested that it would be prudent to limit the rise in global temperature above pre-industrial levels to 1.5°C – as described in a report, IPCC, 2018: Summary for Policymakers:

“Climate-related risks to health, livelihoods, food security, water supply, human security, and economic growth are projected to increase with global warming of 1.5°C and increase further with 2°C.” (see Section B5, and the summary in Figure SPM.2)

The new target of 1.5°C replaces the previous target of 2.0 °C, which was agreed to by the parties to the UN Framework Convention on Climate Change (UNFCCC) in 2015: the ‘Paris Agreement’.  The UNFCCC structure enables targets to be agreed, but allows individual governments to choose the most appropriate way ahead for their individual situations.

The IPCC report is unambiguous about the need to reach net zero quickly, because the maximum temperature reached is determined by the cumulative CO2 emissions up to the time of net zero.[1]  In short, reducing emissions of greenhouse gases more quickly would reduce the need for later removal of carbon from the atmosphere, referred to below as ‘geoengineering’ (

“The energy sector is at the front line of this issue, as it is by far the largest source of the emissions that cause global warming”, as the International Energy Agency (IEA) acknowledges in its Commentary: What would it take to limit the global temperature rise to 1.5 °C?.  This report provides a summary of the available options for the industry and the agency’s estimates of their possible impact.

As described below, changes in behaviour and technical developments need to be encouraged (  Some alternatives to fossil fuels are already available, and these need to be adopted rapidly (  Innovative ways of reducing carbon emissions are possible, and research needs to be accelerated (



[1] Paragraph A.2.2 reads: “Reaching and sustaining net zero global anthropogenic CO2 emissions and declining net non-CO2 radiative forcing would halt anthropogenic global warming on multi-decadal time scales (high confidence). The maximum temperature reached is then determined by cumulative net global anthropogenic CO2 emissions up to the time of net zero CO2 emissions (high confidence) and the level of non-CO2 radiative forcing in the decades prior to the time that maximum temperatures are reached (medium confidence). On longer time scales, sustained net negative global anthropogenic CO2 emissions and/ or further reductions in non-CO2 radiative forcing may still be required to prevent further warming due to Earth system feedbacks and to reverse ocean acidification (medium confidence) and will be required to minimize sea level rise (high confidence). {Cross-Chapter Box 2 in Chapter 1, 1.2.3, 1.2.4, Figure 1.4, 2.2.1, 2.2.2,,,}”

This page is intended to form part of Edition 4 of the Patterns of Power series of books.  An archived copy of it is held at https://www.patternsofpower.org/edition04/3572a.htm