Climate catalyst works in two main ways. Firstly, it speeds up the natural removal from the air of powerful greenhouse gases such as methane. Secondly, it increases the direct cooling influence of clouds, by brightening them and making them last longer in the sky. Clouds are brightened the same way as proposed for Marine Cloud brightening (MCB). The difference is that instead of using evaporated seawater droplets to increase cloud droplet number, microscopic particles of a non-toxic substance perform the same function. When the particles rainout they 'flocculate' (a process used in wastewater treatment, to purify water), removing any potential nanoparticle hazard. They then gradually transform to clay mineral, which is completely inert.

We suggest that an additional safe cooling technology such as climate catalyst should be made available, because it offers additional advantages over MCB. For example, in addition to cooling large areas of ocean and ice sheets, climate catalyst could keep areas at risk of wildfire moist before the fire season. When wildfires do occur, it could reduce the climate warming effect of the smoke by shortening its lifetime in the air. That is because climate catalyst speeds up the natural process by which the smoke particles rain out. It also lightens their colour, which reduces their warming influence in several ways. In addition, climate catalyst helps to protect the ozone layer by preventing smoke particles and other ozone destroyers from entering the stratosphere.

Methane and smoke (black carbon aerosol) are very powerful greenhouse warming agents. If Climate Catalyst proves able to remove them from the air safely and cost-effectively, they represent the 'low-hanging fruit' of climate action. The additional benefit of cloud cooling makes Climate Catalyst an even more compelling proposition.

Existing industry processes and low-cost substances can be used to produce climate catalyst particles. It could be dispersed in remote areas from ships, drones, and land-based dispersal facilities. The bulk of the climate cooling needed could be achieved by dispersing it from existing ships traversing the ocean. Climate catalyst utilizes some of the components of ships' emission gases for its enhanced methane removal chemistry.

Currently Climate Catalyst is a proposal looking for funding to be tested, first in laboratories to develop the safest, most effective formulation, then field trialled to optimize cooling operations. If the trials are successful, we would request regulatory support from governments to ensure it is used in well-coordinated, peaceful, environmentally beneficial ways. Only then should it be scaled up to cool the world's oceans and ice sheets. We accept that even that should be done incrementally, to ensure the effects are always beneficial. Fortunately, if Climate Catalyst needs to be stopped for any reason, it gets rained out of the air within a few days to weeks. At that point it no longer has any direct effect on the climate.

While active in the air Climate catalyst might alter weather patterns, therefore dispersal operations need careful planning. It should be dispersed when/where it is needed in a way that induces favourable weather across the globe on a long-term basis. Such a program would doubtless be controversial and would need to be managed transparently by a trusted intergovernmental body of experienced meteorologists and climate scientists.

Humanity needs to come to terms with the fact that we have profoundly altered the Earth's atmosphere and climate. Therefore, climate cooling interventions will be needed for the foreseeable future until the atmosphere's gas concentrations can be restored to their preindustrial levels.