Soil Health and Climate Change

Agricultural practices play a critical role in feeding the world as well as combating climate change. The health or degradation of our soil is an important part of the solution. Healthy soils produce healthier, more nutritious food; hold more water, thus reducing water runoff; support more plant and animal life above and below ground; and play a significant role in storing carbon pulled from the atmosphere via photosynthesis. The process of photosynthesis depends on plants, and plants depend on healthy soil.

Carbon cycle of a single tree.

In contrast, degraded soil lacks essential soil microorganisms, the ability to absorb water, is vulnerable to wind and water erosion, and loss of nutrient-rich topsoil leading to increased pollution and sedimentation in waterways. 

Over the last several decades, soil degradation has occurred across most of the agricultural lands in the United States due to the use of conventional agricultural practices such as tillage, chemical inputs, monocropping, and exposed soils. With approximately 40% of our nation’s land used in agriculture, repairing our degraded agricultural soils is not only desirable, but necessary to create a stable and healthy food system, water cycle, biodiverse ecosystem, and climate.

Erosion due to unsustainable agricultural practices.

Erosion due to unsustainable agricultural practices. USDA, NRCS, Iowa Soil Erosion Photo Gallery

The Sierra Club supports agricultural policies and practices designed to provide abundant healthy food, fiber and other services for all communities while maintaining and improving the fertility of the soil.

The 4 Per 1000 Initiative

The 4 Per 1000 Initiative ( was started by the French Ministry of Agriculture in December 2015 at the COP 21 international climate conference in Paris. Its members consist of national governments, local and regional governments, NGOs, companies and trade organizations, researchers, and other groups acting together under the framework of the Lima-Paris Action Plan. Sierra Club is an NGO member of the Initiative and participates as a Forum member.

The purpose of the Initiative is to demonstrate that agricultural soils can play a crucial role in mitigating climate change and increasing food security around the world, and to encourage the transition towards a more resilient agriculture that improves soil health, creates jobs, and ensures sustainable development.

Members of the Initiative are encouraged to promote or implement practical actions such as conservation agriculture, agroecology, agroforestry, sustainable landscape management, or other land conservation practices that support these purposes and result in soil carbon storage. 

The Initiative is called 4 Per 1000 because scientists have calculated that an annual average increase of 0.4% of carbon in the soil (4 parts per 1000) deposited in the top 30-40 cm (12-16 inches) of soil would significantly reduce the CO2 concentration in the atmosphere related to human activities. An increase of this amount of carbon in the soil would not only contribute to stabilizing the climate, but would also ensure food security around the world by providing healthy, nutritious food in sufficient quantity.

Picture of cross section of a soil profile.Organic matter in soils plays an important role in four important ecosystem services:

  • Resistance to soil erosion,
  • Soil water retention,
  • Soil fertility for plants and
  • Soil biodiversity.

Even small changes in the soil carbon pool have large-scale effects both on agricultural productivity and on greenhouse gas balance.