Reduction of fossil fuel use
The latest IPCC report puts forward five proposed Illustrative Mitigation Pathways (IMPs), which investigate the plausibility of various climate strategies – all put serious reductions in fossil fuel consumption center stage.
Encouragingly, the report finds that global CO2 intensity decreased by 0.3% per year between 2010 and 2019, a positive sign that is largely attributable to switching from coal to gas and the increasing reliance on renewable energy sources. But this is against a backdrop of steadily growing greenhouse gas (GHG) emissions over the past decades.
Ohlström observes: “It gives us hope, as the recent years’ climate policies have already had an impact—however, the pace should be much faster.”
Indeed, the report leaves no doubt about the urgency to dramatically cut emissions; to stay on track to limit earth’s warming to 1.5°C GHG emissions need to be cut by 45% by 2030, compared to 2019 levels. This will require redoubling of efforts to support measures that have already proven effective and the exploration of novel, radical solutions - this will mainly be driven by a steep reduction in fossil energy sources.
“Renewable energy is truly a more sustainable substitute for fossil-based energy and fossil fuels,” notes Ohlström, echoing the IPCC.
Already credited for contributing to emission reductions, the use of renewables will be key in achieving the increasingly ambitious goals of the coming decades. Solar, wind, and biomass will all play significant roles as energy sources. The cost of solar and wind have decreased by some 85% in the past decade—indicating the increasing viability of their adoption.
Ohlström says there is huge potential in using renewables across different sectors: “Energy systems based on accelerated deep renewable energy penetration and electrification can also provide a pathway to deep mitigation.”
Energy storage, smart grids, sustainable biofuels, and electrolytic hydrogen are some of the specific options that can help with the shift to a more sustainable energy model.
The transport sector is another area where massive reductions in emissions can be achieved. Ohlström emphasizes the need for the increasing use of biofuels as we transition to a fossil-free future; they are a drop-in solution to decarbonize existing fleets likely to be on the roads for decades to come.
“Liquid and gaseous renewable fuels are optimal especially for some transport modes that are difficult to electrify. In addition to climate benefit, renewable diesel burns much cleaner than fossil diesel,” he points out.
A circular economy
The IPCC report notes the importance of circular material flows in everything from industrial production to vehicles, to electricity generation, to construction. Reusing and recycling materials not only cuts down on waste, but it also diminishes the energy required to produce and transport new materials.
Despite this the report reads that circular material flows are “not well represented in climate change scenario modeling.” Ohlström concurs and says that the report does not give sufficient consideration to waste as a potential raw material for sustainable fuels.
“Waste and residues are great raw materials for sustainable biofuels like renewable diesel. They can thus help decrease fossil fuel dependency and reduce emissions,” he says.
Ohlström adds that renewable polymers ought to be part of the conversation as well:
“Using renewable feedstock to substitute virgin fossil oil as raw material for more sustainable plastics is a very promising and growing solution.”
And adds: “When the end product is durable plastic, it can also be recycled over and over again so that the same renewable molecules can be used for new high-quality plastics - further reducing the reliance on fossil resources.”
Carbon capture and storage
Then, of course, there is the question of what to do with the carbon that will be to be emitted in the meantime, as we work toward very low to zero emissions.
The report urges serious reductions in deforestation rates, particularly in significant carbon sinks such as in the Amazon region, as well as the reforestation of regions previously denuded of native vegetation—by about 322 million hectares. These will be critical steps in drawing carbon from the atmosphere.
However, carbon capture and storage (CCS) and carbon capture and utilization (CCU) will also play a role in emission reduction. Without these technologies, fossil-based energy using facilities would need to retire more than two decades earlier in order to limit rising temperatures to 1.5°C.
“Carbon capture from point sources like industrial chimneys is more efficient and economical than the direct air capture that is nowadays discussed on a political level,” Ohlström adds. He explains that in the SHARC project (‘Sustainable Hydrogen and Recovery of Carbon’) which is co-funded by the European Union, Neste plans on both storing carbon dioxide beneath the North Sea and investigating means of using some of the captured CO2 to produce synthetic e-fuels in combination with renewable hydrogen production at the Porvoo refinery in Finland.
Localized approaches will also support decarbonization—the report suggests that individual cities can achieve net zero emissions “if emissions are reduced within and outside of their administrative boundaries through supply chains.”
Further, the report advises retrofitting buildings to make them more energy efficient, supporting the development of public transport, and creating infrastructure that supports non-vehicle transport such as walking and cycling. It advocates that new urban developments create areas that combine employment hubs with housing, use renewable construction materials, integrate renewable, low-emission energy sources, and encourage carbon uptake through features such as green roofs, tree planting, and water features.
Organic fractions of Municipal solid waste is also a promising source of raw material for biofuels and other renewable products—one that would accelerate the circular economy and help replace fossil resources in multiple applications.
Ohlström adds that individual buildings now heated by fossil fuel combustion could benefit from the adoption of more sustainable options like renewable light fuel oil, wood pellets, heat pumps, and by a move to use more renewable electricity.