Plants for carbon farming and China's roadmap for carbon neutralization

Compared to the atmospheric CO2 concentration of 285 parts per million (ppm) in the 1850s, the contemporary atmospheric CO2 concentration is about 415 ppm. Compared to the environment of 1850s, the increase in atmospheric CO2 level already resulted in about 1.5 degrees C in global air temperature and caused major negative impacts on global crop productivity, ecosystem functioning, ocean levels, and human welfare. If the global CO2 level is left uncontrolled, the global atmospheric CO2 level can reach 1000 ppm and the global air temperature can be increased by 5 degrees C, which can cause irreversible and severe consequences on the ecosystem functioning of our planet earth and the welfare of our human civilization. Globally, more and more countries joined the force on developing a carbon neutral society and find ways to mitigate global climate change. The Chinese government announced that China will establish a carbon neutral society by 2060, i.e., by 2060, effective strategies need to be in place to enable capturing the 2.5 billion ton of inevitably released CO2. Various strategies are under development now to realize this goal. The solution may include capturing 0.152 billion tons of C by ocean ecosystem and 0.498 billion tons of C captured by terrestrial ecosystem. Here the carbon capture by terrestrial ecosystem includes 0.068 billion tons carbon captured by marginal land, especially desert, highly arid areas etc and application of biochar equivalent to 0.138 billion tons of C, in addition to the carbon capturing by forest, shrub, grassland ecosystem etc. In addition, 0.054 billion tons of C can be captured by physical or chemical or mechanical techniques for carbon capture use and storage (CCUS). Development of crops for carbon farming will be required to ensure realization of these goals. The features of crops for carbon farming include having high biomass, large root system, very little or zero release of methane and volatile organic carbon molecules, high nitrogen use efficiency, proper soil microbiome conferring high stress resistance and high nutrient uptake and utilization capacity, high resistance for degradation of plant root and residues, perennial, and high tolerance to stresses, such as drought, salinity, high and low temperatures. These features call for concerned efforts in studying molecular mechanisms underlying these traits, and also strategies to realize these traits in current plants. The crops for carbon farming can be developed either through de novo domestication with the support of the modern genome editing techniques, or through manipulation of current crops to gain additional features desired for crops used for carbon farming. Concerted research is also needed to develop better viable strategy to use biochar in agro-ecosystems. Biochar can be used as fertilizers and methods to improve soil quality, in addition to be a major source of carbon sink. Effective combination of photovoltaic electricity generation and plant factory can be used to develop new strategies for plant production in marginal land, which amounts to increase the "land areas" for carbon farming. To expedite development of strategies to enable carbon farming by plants, novel phenotyping and measurement protocols need to be developed to enable detailed characterization of the carbon capture, usage, and storage in different ecosystems, i.e. the forest ecosystem, agro-ecosystem, and ecosystems composed of marginal land. Novel multiscale models also need to be developed to enable not only link ecosystem level fluxes to physiological properties at the leaf, cell or even the organelle levels, which will be required to dissect factors controlling the ability of an ecosystem to capture, use and store carbon, but also to identify new options to further increase the capacity of our ecosystems to capture carbon more efficiently.