This week is the #week4climate all around the world. On Friday the 20th of September millions of people joined the protests around the globe and next Friday, the 27th other cities will follow, including Las Palmas de Gran Canaria. Young people are the ones leading this revolution and since we have lots of students working on our experiment, the motivation was high to join the protests.
However, our experiment doesn´t understand about strikes or weekends, so not working was not an option for us. Anyways, we did try to reach out to the world by explaining why it is so important to not only strike but also to continue searching for solutions for the climate crisis. Some of the students even joined the evening meetings in Las Palmas to discuss the details of the upcoming demonstration. On the streets, more and more people are informed about the facts of climate change, however, not many people know about the path it takes to reach the goals of the Paris Agreement.
While the experimental work continued, we joined the #week4climate protesters from our pier in Taliarte harbour …
We know that the global temperature has already increased by 1°C. We know that the carbon dioxide (CO2) concentration in the atmosphere has reached 400 ppm, which is the highest level in the last 2 million years. The last time the atmosphere had similar CO2 concentrations, temperatures were much higher than anything experienced by humans and sea level was up to 10 meters higher. This means that current atmospheric concentrations are already unsafe and it would be wise to revert to pre-industrial levels around 280 ppm. We are currently emitting 37 gigatons (Gt) of CO2 per year to the atmosphere. To put this into perspective, 1 Gt is 1 billion tons which is about 100.000 times the weight of the Eiffel tower. We also know that we can only emit a maximum of 600 Gt of CO2 more if we want to limit warming to 1.5°C. Thus, at the current emission rate we only have 16 years of business as usual left. To achieve this target, we need to reduce CO2 emissions as fast as possible and reach zero-emissions by 2050. Since the actions required to stabilize climate as desired can only occur gradually and the zero-emission goal seems unrealistic, the path to decarbonization includes deliberate CO2 removal from the atmosphere. By the end of 2030 we must start to remove large amounts of CO2 out of the atmosphere and store them in save reservoirs. This is what scientists call negative emissions.
The oceans contribute naturally to carbon sequestration by taking up one third of the carbon emitted by human activities. However, this occurs mainly through physico-chemical processes. The tiny algae (phytoplankton) that grow at the ocean’s surface also fix carbon through photosynthesis, but to do that they need nutrients that arise with deep waters. When deep water reaches the surface (upwelling) it also brings dissolved inorganic carbon with it and the phytoplankton utilizes it to form biomass following a certain ratio of carbon to nutrients. From the total amount of carbon that is fixed at the surface by phytoplankton, some of it is eaten by zooplankton and transferred through the food web, and only a small fraction sinks to depth. In addition, bacteria remineralize the sinking matter releasing the nutrients and the dissolved inorganic carbon needed for photosynthesis in the first place. Basically, what comes down, goes up again. Therefore, the biological carbon pump doesn´t have a net effect in carbon sequestration from the atmosphere.
So why could artificial upwelling be part of the solution for the environmental crisis? If we would manage to constantly bring those nutrients stored at depth in the ocean to the sunlit surface, this would increase primary productivity, which might lead either to an enhanced trophic transfer (ultimately increasing the fish population), or to an increase in carbon exported and sequestered in the deep ocean. The quantity and quality of this process will vary with the concentrations and ratios of nutrients that we bring up to the surface. For example, if no silicate is available, diatoms, which is a type of phytoplankton that forms it´s walls with silica, will not be able to grow. On the other hand, if plenty of silicate is available, diatoms will proliferate and they might be able to fix more carbon per unit of nutrients having a net effect in carbon sequestration when sinking to depth. Under which conditions and with which communities this might happen, is a fundamental question of our study and of the Ocean artUp project. Hopefully in a few years we will know better how to effectively use artificial upwelling to sequester more carbon from the atmosphere so that it could be used as a negative emission tool. Until then, keep striking, keep demanding action, we, the scientists, stand behind you with the knowledge. #scientists4future
… and from our labs at PLOCAN.