One Earth Climate Model: Keeping the world below 1.5°C with 100% renewable energy

A collaboration between the University of Technology Sydney (UTS), the German Aerospace Center (DLR), and the University of Melbourne (UM) developed a series of advanced regional decarbonization pathways that could limit global warming to 1.5˚C. 

The Paris Agreement, signed by 195 countries in 2016 and ratified by 168 (as of Oct. 11, 2017), establishes a goal of limiting average global temperature rise to well below 2˚C, with efforts to achieve a 1.5˚C limit above pre-industrial levels. Most currently proposed pathways are not sufficiently ambitious to achieve this goal without the reliance upon unproven geoengineering strategies.

The new high-ambition effort hopes to fill this gap by demonstrating the feasibility of achieving the 1.5˚C target through 100% renewable energy by mid-century, combined with a portfolio of natural climate solutions (NCS), including marine and terrestrial conservation, reforestation, and carbon-negative agricultural practices. 

BECCS and other geoengineering strategies have not been proven to work at scale and encourage the continued use of fossil fuels after 2050. Furthermore, strategies like BECCS have significant social and environmental implications, requiring the burning of vast expanses of forest and the potential dislocation of forest-dependent communities.

Renewable energy offers an alternative. In just the past few years the incremental cost per kilowatt for solar and wind generation has dropped rapidly, while the availability of hydrogen and electric vehicles has dramatically increased. At current rates of growth, the world could meet approximately 12.5% of its energy demand with renewables by 2020, allowing for a rapid expansion of the renewable energy sector as legacy combustion plants are retired in the 2020-2040 timeframe.

Announced at the 23rd Conference of Parties (COP23) of the UN Framework Convention on Climate Change (UNFCCC) held in Bonn, the high-ambition climate scenario will break down demand and conversion for all four energy sectors -- power, buildings, industry, and transport – across 10 regions. The power sector of each region will be modeled in hourly increments to assess storage demand and demand-side management options for the integration of high percentages of variable energy sources, such as solar and wind.

The project will utilize the MAGICC platform (Model for Assessment of Greenhouse Gas Induced Climate Change), taking into account a wide range of greenhouse gas sources. In addition to energy-related carbon and methane emissions, the model will incorporate emissions from deforestation and land-use change and emissions from the agricultural sector.

We are pushing the limits of ambition, because we must. We just reached 1˚C in global warming and already we are seeing disastrous consequences. It is a moral imperative to keep the world below 1.5˚C, and we believe 100% renewable energy, combined with natural climate solutions, could get us there. — Karl Burkart, Deputy Director, One Earth

The transition to renewable energy will require a significant investment of capital, a point often made by critics of high-ambition energy scenarios. But governments are currently providing massive subsidies to fund the ongoing extraction, transportation, and processing of fossil fuels, which are responsible for 70% of the greenhouse gas emissions driving climate change. A new study published in the journal World Development places total fossil fuel subsidies at $5.3 trillion in 2015 alone. 

Diverting just a portion of these subsidies to renewable energy would unlock a massive acceleration in clean energy supply, providing enormous societal benefits. A paper published in Joule estimates that switching to 100% renewable energy would create an additional 24 million long-term jobs; decrease more than 4 million pollution-related deaths per year; and provide annual savings of over $20 trillion in health and climate impact costs through 2050. 

Even without subsidies, renewable energy is now becoming cost-competitive with conventional coal or gas-powered thermoelectric plants in many regions, and far less costly than new nuclear plants, making it an appealing option for both developing and OECD countries.