Scenarios about the energy system
By now, it is clear that the main sustainability issues are very serious and the impacts are huge. Research has shown that about half of the cumulative anthropogenic carbon dioxide emissions between 1750 and 2010 were emitted over the last 40 years. But what does the future possibly look like? Countless scenarios have been developed over the years in order to predict possible pathways and to show how we could avoid more severe consequences.
The International Panel on Climate Change (IPCC) has assessed about 900 mitigation scenarios, with atmospheric concentration levels in 2100 from 430 to above 720 ppm CO2. Baseline scenarios project the CO2 emissions from the energy supply sector to double or even triple by 2050 compared to the 2010 level of 14.4 Gton CO2/year. To avoid this, improvements in energy intensity have to be accelerated. The mentioned limit of 2-degree Celsius increase (compared to pre-industrial levels) is characterised by an atmospheric concentration of about 450 ppm CO2-equivalent. The scenarios that opt for this 450 ppm limit generally contain very rapid improvements in energy efficiency and a very steep growth in zero- and low-carbon energy supply. The share of renewables, nuclear energy and fossil energy with additional carbon capture and storage (CCS) will triple or even quadruple in those scenarios. Overall, the global changes in the energy supply system will reach reductions of more than 90% below 2010 levels between 2040 and 2070.
Developments in infrastructure and long-lived products have the capability to lock society into pathways with high greenhouse gas emissions and they will be very difficult and costly to change. It is therefore important to realize mitigation measures today, because waiting until 2030 before taking action, is estimated to heavily decrease the possibilities for a transition. Population and economic growth remain the two most important drivers of increasing CO2 emissions from fossil fuel combustion. While the contribution of population remained somewhat stable, the contribution of economic growth to emissions has risen sharply. But because of the differences in those two drivers between countries, also the specific mitigation efforts and related costs will differ per country and per scenario. The cost-effective scenarios state that the countries with the highest predicted future emissions have to undertake the majority of the mitigation efforts.
The IPCC has made an extensive assessment of the literature on scientific, technological, environmental, economic and social aspects of mitigation of climate change. The ‘Summary for Policymakers’ is a useful read if you’re interested in pathways and scenarios to change the energy system.
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