main strategies, globally, by adding tax and dividend. The constraints, from my perspective, mostly will be differentiation of developing and developed countries. For the developed one, it's easy to fulfill the requirement since their technology improve drastically for these few decades. On the other hand, developing countries are still struggling with their technology. Their industries right now, rely on old technology with such low efficiency, a technology that already forgotten by developed countries for years, but they have no other choice. They also being pushed to keep their forest and so on while they need to emerge if they want to grow their economy. It is unstoppable. Also, most of their upstream consumers are the developed countries, especially raw material such as wood, coal, etc that have huge impact on environment. It even harder for the poor countries, with carbon tax, how could the even grow to developing countries?

And the most donor of our carbon foot print were the developed countries, for years. It is unfair to share their burden with countries that do nothing in the past decades.

Dear Qoriatul Fitriyah, thank you very much for your insightful comments. Regarding the technology-maturity, the cost-effectiveness, and the energy appreciation/viewpoint of these technologies which is the current mainstream?

According to J. Yan, among the three main CO2 capture technologies, post combustion capture R&D is receiving the most emphasis, followed by oxy-combustion and then pre combustion capture. While in most regions, CO2 sequestration R&D is proportionately similar to that devoted to post-combustion capture R&D.

CCS is one of the future technology options for achieving the 2 degree target of global climate change in 2050. Scientific research and technology development as well as the small-scale pilot test play an important role for the future implementation of the technologies.

I assume that by strategies the question refers to CCS technologies rather than how CCS is deployed.

The first approach to reducing GHG emissions is to improve energy efficiency: reducing the amount of CO2 to capture alleviates the cost of CCS. So, improve the efficiency of energy production (power generation, motive power etc.) and energy usage (motor drives, thermal insulation etc.), and deploy renewables and nuclear as widely as economically possible. Limiting the use of coal is also an important step but this will not be an economic option for many of the developing nations.

Help nature to remove CO2 from the atmosphere by planting more trees and preserving the rain forests. Use resources more efficiently by increasing recycling. Reduce food waste; produce has a CO2 footprint from fertilization, handling and transportation, and so too does the waste from transportation handling and methane release during decomposition. These are some of the measures that citizens have under their control.

Once all this is done there will be less CO2 released but still a great deal of which to dispose. The major source of CO2 will remain fossil fuels and post- and pre-combustion CCS are the most likely technological choices and are commercially mature. Oxy-combustion I suspect will not be widely deployed. The CO2 will mainly be stored geologically but a lesser amount will be utilised in the cement and chemical industries. To avoid releasing any CO2, reforming natural gas (or gasifying coal) for hydrogen production is being proposed. For CO2 already in the atmosphere, direct air capture (DAC) and biomass energy with CCS (BECCS) are being proposed.

Post-combustion is being used on 250-MW slip-stream at an NRG coal-fired plant in Texas (Petra Nova project) and at several other locations around the world, albeit at a smaller scale. The Petra Nova project uses an MHI solvent but solvents are available from other suppliers, and R&D may eventually identify improved solvents. The capture process is a cost burden to the power plant and reduces net output, but these costs are offset by using the CO2 for enhanced oil recovery. The project has already announced that once the oil field is depleted that the capture plant will be closed. If capture projects are to proceed society will have to accept increased costs for the benefit of the planet.

There are many hundreds of coal/pet coke gasification projects producing hydrogen for chemical and fertilizer but regrettably, the CO2 is mainly vented to atmosphere but could equally be captured and stored, always provided the costs can be covered. A gasifier project in Wabash Indiana will produce hydrogen for fertilizer production and store the CO2 (~1.5 million tonnes per annum), the storage project being a demonstration funded by the US DOE.

To avoid releasing small point sources of CO2 from natural gas-fired units such as domestic boilers and commercial buildings, it is proposed to convert the natural gas to hydrogen and capture and store the CO2 released. Two such projects are being proposed in the UK by Northern Gas Networks and Cadent. In Scotland hydrogen is being produced by electrolysis to fuel fuel-cells in buses and also to displace diesel used in the Orkneys' ferries.

DAC draws air over a solvent membrane, which when saturated is heated to release the CO2. This may be more suited to providing the CO2 for small-scale chemical production rather than storage, but it has the support of Bill Gates and may evolve into a more attractive solution than it appears today. BECCS burns biomass, which stores CO2 during photosynthesis, and the CO2 released during combustion is captured and stored resulting in a net reduction in atmospheric CO2.

There is no shortage of technological options for the deployment of CCS, all that is lacking is the political will. Today in the UK, the elections for the European Parliament will be a bellwether of public opinion on Brexit. Climate change needs to be brought to the ballot box and force politician’s hands in tackling climate change.