The Relationship And Interplays Between Land And Climate Change

In the month of August, the Intergovernmental Panel on Climate Change or the IPCC in short, released a report on climate change and land. The IPCC is the body whose scientific work guides policy around climate change.  In this report, scientists assessed a wide range of material concerning the interplays between land and climate change.

In it, the IPCC starts by noting that only a quarter to a third of land’s potential net primary production is being utilized. It observes that ‘land provides the principal basis for human livelihoods and well-being including the supply of food, freshwater and multiple other ecosystem services, as well as supporting biodiversity’.

Now, land is both a source of emissions where it releases greenhouse gases, as well as a sink, where it absorbs them. It is important to note that all aspects of the physical environment are interconnected. Land therefore plays a huge role in the exchange of energy, the hydrological, nitrogen and carbon cycles.

The report states that as global population increases, there has been more pressure on land especially as agriculture expands in order to satisfy food consumption. Agriculture accounts for 70% global freshwater use. The expansion of areas under the same and commercial forestry has led to loss of natural ecosystems and the resulting loss in biodiversity.

Greenhouse gas emissions have significantly increased since the preindustrial era and have resulted in an increase of global air temperatures, which is the cause of the current climatic changes. According to the report, Agriculture, Forestry and other Land Use changes (AFOLU) are responsible for 23% of global greenhouse gas emissions from 2007-2016. In the same period, land has absorbed the equivalent of 29% of carbon dioxide emissions.

agriculture - picture courtesy of world agroforestry

The relationship between climate change and land is often complex, with one affecting the other. For example, climate change contributes to desertification and land degradation. It does this through the effects of droughts, flooding, intense rainfall, heat waves and dry spells, sea level rise, wave action leading to coastal erosion and wildfires all of which are exacerbated by climate change.

Frequent, intense and longer droughts dry up surface water and the soil, loosening it up and making it more vulnerable to erosion. High temperatures and increased rates of evapotranspiration cause desertification. Desertification causes vegetation loss and thus the release of more emissions. Intense rainfall and resultant flooding naturally loosens, erodes and carries away topsoil, which then negatively affects agriculture and food security, as well as human lives and livelihoods.

Climate change also has reduced both the yield and nutritional content of crops especially in the tropics and lowered the growth rate of animals in pastoralist systems. This could have profound implications for the food security of many African countries, whose economic mainstay as well is rain fed agriculture.

Higher temperatures coupled with lack of enough rainfall also increase the severity of wildfires. This not only adds emissions but also degrades land. Forests and dry lands are especially vulnerable to this because of the large acreage.

As a result of climate change, arid climate zones are widening and polar climate zones are contracting. This affects biodiversity because plant and animal species which don’t adapt or disperse fast enough face extinction.

The report notes that on a global scale, there is more vegetation greening than browning though this differs on a regional and local scale. Africa for example is on the receiving end of climate change extremes and resultant effects.

Sea level rise and wave action, both as a result of climate change worsens coastal areas, by destroying mangroves and eroding beaches as water continues to creep inland. The Kenyan coast is gravely affected because sea level rise in particular has led to salt water intrusion thus rendering previously agricultural land infertile and affecting the quality of drinking water.

Permafrost (frozen soil) thaw in the arctic as a result of higher temperatures is also releasing both methane and carbon dioxide, which further increases climate change. There is also increased incidence of dust storms in the Middle East and in Asia with negative consequences on human health.

But how does land itself act a source of emissions? Well, first is emissions released from deforestation. Trees absorb carbon dioxide in photosynthesis and store it up in their trunks. When trees are cut and used, all these emissions are released into the air.

As a direct result of human interference, the rate of soil erosion is up to a hundred times more than the soil formation rate. This is particularly poignant in light of the fact that the soil acts as a carbon sink.

Agriculture is the third largest emitter of greenhouse gases per sector globally. Flooding of rice paddies and livestock rearing releases methane, a greenhouse gas. Nitrous oxide is released from application of nitrogen based fertilizers in farms as well as from decomposition of animal manure. 

Clearing of land by burning and other practices not only releases soil carbon, but also kills useful soil microbes and worms.

Food loss and waste releases emissions when stored in landfills. Nitrous oxide, methane and carbon dioxide is released from the process. In fact, the United Nations has previously said  if food loss and waste was to be indexed as a country, it would be the third largest emitter in the world. 

Indirectly, use of farm machinery releases emissions as well.

Peat lands are areas where there is a very low rate of bacterial decomposition because of conditions such as waterlogged soil. This means that plant residue is just left in the soil as it is. Over time this accumulates forming very rich carbon deposits. Due to commercial pressures, peat lands are being cleared at an unprecedented scale. Such areas when burnt, drained or mined release emissions at a very high rate.

Due to human influence on land, whereby vegetation covering is removed, there has been an increase in global albedo (surface reflectivity) and this is touted to lead to surface cooling in the long run. The overall effect however is minimal. In reality, bare vegetation-less land is just hotter than land that is say, covered by forests and trees.

a sand dune in the Sahara desert - picture courtesy of express

Urbanization is also another type of land use that contributes to climate change and leads to higher city temperatures known as the heat island effect.

Climate change will lead to environmentally induced migration as people flee inhospitable conditions and seek better climes with sustained food security and sure livelihoods. This is set to stir up conflict.

So what is the way forward? Well, sustainable land management for one. Improved management of crop and pastoral land systems ensures maximum productivity without increasing emissions. The Paris Agreement has as one of its objectives to reduce emissions from agriculture without negatively affecting food production.

Other solutions include soil organic carbon management as well as climate smart agriculture. For example, planting drought tolerant crop varieties which also mature faster. We should also break our over reliance on a limited number of food crops by diversifying and multiplying the kind of plants we grow. Practices such as mulching and cover crops also protect soils while absorbing carbon.

There is need for better dietary choices by lowering consumption of livestock products which not only cuts emissions but also reduces pressure on land. Livestock breeds with higher production as well as higher tolerance to harsh climatic conditions should be reared. There should also be better management of pasture and rangeland systems. Reduction of post- harvest loss and adoption of better storage practices can curb food loss and waste.

Restoration and conservation of natural ecosystems is recommended. Afforestation, reafforestation as well as agroforestry would all increase forest cover as well as provide food and other ecosystem services. Ecosystem based adaptation would bring climate benefits but also reduce land degradation.

Conservation of peat lands is also a good measure in order to protect carbon deposits and in fact, further re-vegetating them is beneficial to the planet. Another thing is to reduce competition for land, ensure more effective fire management and soil management measures.

The IPCC report further notes that it is necessary to include all stakeholders especially local communities in providing solutions for land management. This is because they are in daily contact with the environment. These communities also offer indigenous knowledge, which is an important tool in the fight against climate change. Public education and participation is also encouraged especially in promoting better health policies and dietary choices. Better health insurance, financial incentives and awareness campaigns would also contribute to such.

Clean energy also reduces overexploitation of forests for fuel. It therefore reduces land based emissions from deforestation.

It is notable that effecting measures to counter land degradation also contributes to poverty eradication and benefits food security.

The report continues to cite insecure land tenure, improper land zoning and spatial planning as problems which when properly addressed and corrected will yield benefits in relation to land degradation and climate change.

Women empowerment is vital as women are disproportionately affected by climate change because of their reliance on land for its services. However, due to land ownership practices they do not have a voice concerning its use and management.

The report concludes by noting that there is hope if we work to conserve land as it not only has multiple benefits, but it also helps protect the planet from harmful climate change.