The effects of climate change are already here, and they become more dire and irreversible by the day. For humans, the ultimate goal when it comes to carbon dioxide emissions is to get the number down to zero.
While this may seem an unreachable goal currently, it’s one that we need to accomplish within the next several decades in order to avoid disastrous consequences. Getting there will require a great deal of hard work and innovation, as some industrial sources of atmospheric carbon do not have affordable emissions-free substitutes, says a new study in Science.
“We wanted to look closely at the barriers and opportunities related to the most difficult-to-decarbonize services,” says lead author Steven Davis of the University of California, Irvine.
Although human activities that contribute greatly to atmospheric carbon include heating, cooling, lighting, and motor vehicles, there are other significant contributors that pose much more of a challenge when it comes to finding alternative no-emission or low-emission options. These contributors include air travel, freight trains and ships, and the manufacturing of steel and cement.
The researchers analyzed a number of barriers to the zero-emissions goal, such as the expected increase in demand for both air travel and freight shipping – which already contribute to roughly 6 percent of global emissions. Additionally, the manufacturing of steel and cement release 1.7 and 1.3 billion tons of carbon dioxide into the atmosphere each year, which is only expected to increase as infrastructure demands increase.
“Taken together these ‘tough-nut’ sources account for a substantial fraction of global emissions,” says Ken Caldeira of the Carnegie Institution for Science. “To effectively address them, we will need to develop new processes and systems. This will require both development of new technologies and coordination and integration across industries.”
The research team also assessed potential new technologies that could bring us closer to our goal. This includes the synthesis of energy dense hydrogen or ammonia-based fuels for aviation and shipping, new furnace technologies in steel and concrete manufacturing, and possible tools to capture and safely store hydrocarbon emissions. In their assessment, they warn that the costs of implementing and scaling these technologies will be a massive hurdle. Furthermore, it will be difficult to overcome the inertia of existing systems and policies in order to make room for new technology.
“We don’t have a crystal ball to foresee what technologies will exist a century from now,” Caldeira says. “But we know that people will want buildings, transportation, and other energy services and we can try to design our energy system so that it is able to take advantage of new inventions as they come along.”