Climate disruption caused by the emission of greenhouse gases heat trapping pollutants was predicted by Earth science researchers decades ago.
The recent intensification of extreme events including abnormal temperatures massive wildfires and floods has begun to motivate more governments companies researchers and concerned citizens to act in order to limit the rise in greenhouse gas concentrations in the atmosphere and prevent further disasters and damage.
Reports by international climate assessment bodies determine that limiting the rise in carbon dioxide concentration the main anthropogenic greenhouse gas will be achieved mainly through emissions reduction whether by improving energy efficiency transitioning to renewable energy sources primarily solar and wind or by capturing carbon dioxide at power plant chimneys and storing it in suitable geological formations or in the deep sea.
These approaches contribute to most of the planned reductions which most countries of the world committed to under the Paris Agreement to reduce greenhouse gas emissions.
However the agreement recognizes that there are emission sources where reduction or capture at the point of emission is difficult such as aircraft and therefore carbon dioxide removal from the atmosphere itself will also be required.
Atmospheric carbon removal is now gaining significant attention leading many to see it as a technological magic solution that eliminates the need for emissions reduction and far reaching changes in the economic system and lifestyles.
The proposed methods for atmospheric carbon capture are divided into purely technological approaches such as systems that filter air capture carbon dioxide from it and transfer it for storage and nature based solutions which cause changes in natural ecosystems.
Nature based approaches include among others enhanced weathering of minerals based on spreading crushed igneous rocks such as basalt on agricultural fields adding crushed limestone to ocean waters fertilizing oceans with iron planting forests growing plants as fuel biomass for power plants and capturing the carbon dioxide produced during combustion burning organic residues and converting them into biochar restoring wetlands and creating new wetlands optimal forest management while producing long lasting wood products.
Clearly the scope here is too limited to explain each method in detail but it is clear that a promising method is one that allows capturing significant amounts of carbon from the atmosphere at a reasonable cost currently less than one hundred dollars per ton of carbon without causing new environmental or social problems.
Examinations show that none of the proposed carbon capture technologies is mature enough for use at the scale required to significantly slow climate disruption.
Many of the methods require large energy investments for example rock grinding or direct air capture.
It would of course be absurd to operate an air capture system powered by fossil fuels.
Supporters of these methods argue that the energy will come from renewable sources wind and solar but as long as most global energy demand is not supplied by such sources it is more effective to invest in a comprehensive transition to renewable energy rather than investing in atmospheric carbon capture while widespread fossil fuel use continues.
Other ideas such as forest planting are exposed to the dangers of climate disruption itself which will cause increased droughts and forest fires.
Many other methods involve high costs that are unclear how they can be reduced in the foreseeable future while others simply lack the potential to remove enough carbon even if widely implemented. Some methods such as proposals to fertilize oceans endanger the ecology of natural systems while others such as growing plants for energy production on agricultural land threaten food security.
A central danger is that the supposed magic solution causes the public to believe that a simple and easy way will be found to avoid climate disruption and therefore there is no need to address alarming forecasts.
It appears that despite the good intentions of many who promote atmospheric carbon capture its promotion generates another wave of denial of the need for action now.
The approach heard among decision makers and advisors according to which one should wait for the development of carbon capture technology and until then continue as usual diverts public attention from the need to change behavior and invest resources in proven solutions.
As a result actions such as increasing energy efficiency expanding the use of solar and wind energy capturing carbon dioxide at power plants and storing it in geological reservoirs expanding public transportation building walkable cities and climate adapted buildings are not adequately funded if at all.
However even though there is currently no promising method for atmospheric carbon capture it is possible that such a method will be discovered in the future.
Therefore it is still worthwhile to invest in research on the subject but funding must be directed only to proposals that have undergone rigorous preliminary evaluation and not at the expense of proven approaches to emissions reduction.
Ultimately the public must recognize that addressing climate disruption will require significant efforts and resources and carbon capture can serve only as a complementary tool to be developed alongside substantial and widespread emissions reduction.