The principal idea of enhanced weathering (EW) as a climate solution is to mix rock dusts into the soil to reroute a fraction of the natural carbon cycle through trapping CO2 into the leachate water in the form of bicarbonates which are ultimately stored in the oceans. It is a nature-based method that effectively copies Earth’s time-tested natural method to control its atmospheric CO₂ concentration through natural rock weathering.  However, weathering of added rock dusts in the complex soil environment needs more time and research to be fully understood. This could delay the required larg ..read more

Data from our greenhouse, part 3 Background We present insights we gained from CO₂ efflux, soil pCO₂ and soil water leachate alkalinity data of 400 greenhouse experiments for enhanced weathering (EW), a promising new approach to carbon dioxide removal (CDR) which uses rock dusts on agricultural soils to capture CO₂. Methods We monitored hundreds of soil-rock dust combinations in a controlled greenhouse setting using fluxmeters, sensors, and high frequency leachate analyses combined with data analytics to better understand change in soil carbon fluxes and pools. Results Our findings reveal that ..read more

Why and how we built our army of autonomous CO₂ fluxmeters Blog article - V1.0 - Feb 8th 2024 - Dirk Paessler, Ralf Steffens, Jens Hammes, Anna Stöckel, Ingrid Smet Introduction Download a PDF of this document (5 MB) Enhanced weathering (EW) is expected to become one of the keystones to fight climate change by capturing CO₂ from the atmosphere and storing it underground and in the oceans at reasonable cost. However, as the exact inner workings of the involved processes are not yet fully understood, a lot more scientific data is needed for the ongoing development of this carbon dioxide removal ..read more

Last week, exactly 365 days after setting up the first experiments, we have extended our greenhouse experiment with 78 new lysimeter experiments to now close to 400 experiments in total. We are closely following last year’s building recipe, of course. Again we are using the LUFA 2.2 soil and LUFA 6S soil to which we have added 6 rock dust amendments: basalt, dunite, steel slag (all three are the same as last year), plus three new ones: calcite (“lime” from Müllerkalk), crushed concrete (from university FAU Erlangen) and a superfine glacial dust from Greenland (from University of Copenhagen). T ..read more

Blog article - Dirk Paessler, Jens Hammes, Ralf Steffens, Ingrid Smet - 21.1.2024 - V1.0 Abstract In our endeavor to measure the climate relevant effects of rock weathering in agriculture we have been setting up several field and greenhouse experiments over the last three years. During this work we started experimenting with low cost electronic sensors in 2022 with the goal to monitor the soil gas CO₂ concentration (pCO₂) in our enhanced rock weathering (ERW) experiments, mainly in lysimeters in fields and greenhouses.  In this article we document our latest sensor design which gives us ..read more

Here is a look at Carbdown’s year 2023 with a collection of videos about our work! Picking up our holiday tradition we have a special, final blog post for 2023 for you. Last year we published a photo album of rock weathering projects around the world. This year we invite you to a TV session with videos about us and our projects, all of them published in the last 12 months. We started the year with the setup of our greenhouse project. 25 scientists came to Fürth and helped us to set up almost 400 lysimeter experiments. Our resident youtuber Patrick has produced a nice video about these two days ..read more

(Image by DALL-E for Carbon Drawdown Initiative) We update our document from 3 weeks ago about estimating carbon dioxide removal (CDR) by enhanced rock weathering (ERW) using measurements of alkalinity in leachate waters. When we continued to work with the data for follow-up articles, we unfortunately found a mistake in one calculation. For full transparency we are documenting this error and some improvements to the uncertainty estimates in our update. The two substantial updates are as follows: We have improved our statistical approach to calculate reasonable estimates of the error ranges ..read more

by Dirk Paessler - 6.12.2023 - V0.3 The following is a thought experiment, a simplified approach to address this question. We are not even trying to do an exact calculation here, because it isn’t clear if we will ever be able to find an exact answer given the complexity of the ERW system with its multitude of processes and parameters. We just want to understand “where in the ballpark” the greenhouse’s increase of the weathering rate might be.   How do we “transfer” weathering rates measured in our greenhouse to the outside world? We wanted to get an understanding on how much faster ..read more

Join us on our endeavor to reliably measure the climate-positive effect of enhanced rock weathering (ERW) in agricultural settings by analyzing the water that leaches from the soil! In this blogpost we explain how the carbon dioxide removal (CDR) effects of rock weathering can be estimated using alkalinity measurements of leachate water and what early results we see in our greenhouse experiment.   Introduction In this paper we delve into Enhanced Rock Weathering (ERW) and its potential for Carbon Dioxide Removal (CDR) in agricultural settings. We present the first results of our extensiv ..read more

Hundreds of sensors monitor the weathering processes of 400 climate experiments for enhanced rock weathering in the Project Carbdown greenhouse. Some send new data as often as every few seconds. This article explains why we use high frequency monitoring on a slow process and how we handle and analyze more than 4 million data points per day in real time using various cloud services while keeping cost below €150 per month. Real-time monitoring meets weathering Data Several unique aspects set the Carbdown greenhouse experiment apart: It is an extensive setup with 400 experiments (100 variations ..read more