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Put more carbon back in soils to meet Paris Climate Pledges, opinion piece from the 4 per 1000 initiative.

16th Jan 2019

This piece was published in Nature at the end of last year (just before the climate change talks in Katowice) and challenges us all to take 8 steps to make our soils more reslient to drought, produce more food and store emissions.  For more information on the 4 per 1000 initiative, please click here. 

To read the full article in its original format please click here

Soils are crucial to managing climate change. They contain two to three times more carbon that the atmoshere. Carbon is also esential for soil fertility and agricutlure. Decomposing plants, bacteria, fungi and soi lfauna such as earthworms, release organic matter and nutrients for plant growth, including nitrogen and phosphorus. This gives structure to soil, making it resilient to erosion and able to hold water. 

Increasing the soil carbon content of the world's soils by just a few parts per thousand (0.4%) per year would remove an amount of CO2 from the atmosphere equivalent to the fossil fuel emissions of the European Union (around 3-4 gigatonnes Gt). It would also boost soil health. 

Improving soil carbon is now high on the political agenda. In 2015 at the Paris climate summit, France launched the 4 per 1000 initiative - to promote research and actions globally to increase soil carbon stocks by 4 parts per 1000 per year. They are 8 steps below which should be focussed on to get the most out of projects, direct new research and show evidence.

1. Stop carbon loss

Protecting peatlands is the first priority for keeping existing carbon in the ground. These hold between 32 and 46% of all soil carbon. Each year they take up about 1% of the global CO2 emissions that are generated by humans. And we don't just need to protect peatlands, degraded mineral soils also need to be restored by controlling grazing, applying green manure or growing cover crops.

2. Promote carbon uptake

Researchers need to establish a set of best practices for getting more carbon itno soil. Proven techniques including making sure the soil is planted all year round, adding crop residues such as mulch and straw or compost and minimising tillage practices such as ploughing. Soils need regular inputs of organic matter, and care needs to be taken especially where there are competing demands for crop residues. Regional strategies for increasing soil carbon need to be developed, taking into account local soil types, climates, rates of climate change and socio economic contexts. In Europe, reducing mineral fertilisers and implementing agriecological practices would be effective.

3. Monitor, report and verify impacts

Researchers and land managers need to track and evaluate interventions. Large scale, long term frequent monitoring is expensive and invoves extensive field surveys, and must continue for at least 10 years. 

4. Deploy technology

Advanced equipment makes soil measurements cheaper, faster and more accurate. Portable infrared spectroscopes will soon be capable of tracking multiple chemical signals in soil, including carbon. Harmonised methodologies, verified standards and common guidelines will be needed for all these devices. Satellite imagery is also essential. Researchers should also develop automatic processes and algorithms for assessing soil carbon content from space, or for predicting it from the characteristics of vegetation. THese methods will need ground truthing and calibrating.

5. Test strategies

Computer models and a network of field sites need to be developed to test the effectiveness of different management strategies. Farmer shoud report their actions, and data on soil types and weather patterns will need to be collected. Soil data needs to be more transparent and accessible.

6. Involve communities

The public should be made more aware of the importance of soil organic carbon and of their abiltiy to improve it on farms, in private gardens and public areas. Citizen science approaches to collecting data should be extended to soils. A global open online platform to collect and share soil carbon data needs to be established.

7. Coordinate policies

Political frameworks covering soils and climate change should work together. Targets and policies will be needed to reford agricutlural practices worldwide, which will take time. Farmers will need incentives to change their methods.

8. Provide support

Policy makers should include soil carbon in emissions trading schemes and carbon taxes. This will be harder that schemes for CO2 because soil carbon is transient, unevenly distributed and harder to measure. Development banks and investors should create global investment funds to support practices that improve soil carbon. 

What next?

First researchers, policymakers and land managers need to recognise that increasing soil carbon stocks and protecting carbon rich soils is crucial for achieving the Paris climate targets and SDGs. Second, international funding agencies should set up a pool of several million dollars to address urgent research gaps, such as those identified by the 4 per 1000 intiative. These include estimating the potential for soil carbon storage; developing targets and management practices; designing targets and management practices; designing monitoring, reporting and verification strategies and understanding basic soil plant processes. 

Source: Nature comment, vol 564, 6 December 2018