18 countries showing the way to zero carbon

From The Conversation:

Eighteen countries from developed economies have had declining carbon dioxide emissions from fossil fuels for at least a decade. While every nation is unique, they share some common themes that can show Australia, and the world, a viable path to reducing emissions.

Global CO₂ emissions from fossil fuels continue to increase, with record high emissions in 2018 and further growth anticipated for 2019. This trend is linked to global economic growth, which is largely still powered by the burning of fossil fuels.

Significant reductions in the energy and carbon intensities of the global economy have not been sufficient to trigger decreases in global emissions.

But 18 countries have been doing something different. A new analysis sheds light on how they have changed their emission trajectories. There is no “silver bullet”, and every country has unique characteristics, but three elements emerge from the group: a high penetration of renewable energy in the electricity sector, a decline in energy use, and a high number of energy and climate policies in place. Something is working for these countries.

The 18 countries shown below all peaked their fossil fuel emissions no later than 2005 and had significant declines thereafter to 2015, the period covered by our study.

Changes in CO2 emissions from fossil fuel combustion for 18 countries with declining emissions during 2005-2015. Countries are ordered by how soon their emissions peaked and began to decline. Le Quéré et al. Nature Climate Change (2019) based on data from the International Energy Agency @IEA/OECD.
2005=0

Uniformly, the largest contribution to emissions reductions – about 47% – was due to decreases in the fossil share of energy production, while reductions in overall energy use contributed 36%.  However, there are large differences in the relative importance of the factors that drove emissions reductions in the various countries. For instance, reduced energy use dominated emissions reductions in many countries of the European Union, whereas a more balanced spread of factors dominated in the United States, with the single largest contributor being the switch from coal to gas. Emissions reductions in Austria, Finland and Sweden were due to an increased share of non-fossil and renewable energy.

Interestingly, our analyses suggest that there is a correlation between the number of policies to promote the uptake of renewable energy and the decline in the 18 countries.

Emissions declined by 2.4% per year during 2005-15 across the 18 countries.

One could argue this decline is not particularly meaningful because global fossil fuel emissions continued to grow at 2.2% per year during the same period. However, this group of countries is responsible for 28% of the global CO₂ emissions from fossil fuels. That is a sizeable fraction, and if the decline continues and further intensifies it can have a significant impact. 

If global emissions were to fall by 2.4% per annum, by 2050 they would have fallen 52%.   That's not enough.  But a small increase makes a big difference over 30 years.  At an annual decline of 3.5%,  only 1.1% more per annum, by 2050 emissions will have fallen by 2/3rds, by 2060 75%, and by 2100  95%.    So if these countries could step up their attempts to cut emissions by just 1% per annum, and if other countries would also commit to a 3.5% annual cut in emissions, we might limit global warming to 2 degrees C.  There's hope.  It can be done, whatever the denialists say.