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UN climate change report: land clearing and farming contribute a third of the world’s greenhouse gases

05 September 2019 | Adaptation

We can’t achieve the goals of the Paris Climate Agreement without managing emissions from land use, according to a special report released today by the Intergovernmental Panel on Climate Change (IPCC).

Emissions from land use, largely agriculture, forestry and land clearing, make up some 22% of the world’s greenhouse gas emissions. Counting the entire food chain (including fertiliser, transport, processing, and sale) takes this contribution up to 29%.

The report, which synthesises information from some 7,000 scientific papers, found there is no way to keep global warming under 2? without significant reductions in land sector emissions.

Land puts out emissions – and absorbs them

The land plays a vital role in the carbon cycle, both by absorbing greenhouse gases and by releasing them into the atmosphere. This means our land resources are both part of the climate change problem and potentially part of the solution.

Improving how we manage the land could reduce climate change at the same time as it improves agricultural sustainability, supports biodiversity, and increases food security.

While the food system emits nearly a third of the world’s greenhouse gases – a situation also reflected in Australia – land-based ecosystems absorb the equivalent of about 22% of global greenhouse gas emissions. This happens through natural processes that store carbon in soil and plants, in both farmed lands and managed forests as well as in natural “carbon sinks” such as forests, seagrass and wetlands.

There are opportunities to reduce the emissions related to land use, especially food production, while at the same time protecting and expanding these greenhouse gas sinks.

But it is also immediately obvious that the land sector cannot achieve these goals by itself. It will require substantial reductions in fossil fuel emissions from our energy, transport, industrial, and infrastructure sectors.

Overburdened land

So, what is the current state of our land resources? Not that great.

The report shows there are unprecedented rates of global land and freshwater used to provide food and other products for the record global population levels and consumption rates.

For example, consumption of food calories per person worldwide has increased by about one-third since 1961, and the average person’s consumption of meat and vegetable oils has more than doubled.

The pressure to increase agricultural production has helped push about a quarter of the Earth’s ice-free land area into various states of degradation via loss of soil, nutrients and vegetation.

Simultaneously, biodiversity has declined globally, largely because of deforestation, cropland expansion and unsustainable land-use intensification. Australia has experienced much the same trends.

Climate change exacerbates land degradation

Climate change is already having a major impact on the land. Temperatures over land are rising at almost twice the rate of global average temperatures.

Linked to this, the frequency and intensity of extreme events such as heatwaves and flooding rainfall has increased. The global area of drylands in drought has increased by over 40% since 1961.

These and other changes have reduced agricultural productivity in many regions – including Australia. Further climate changes will likely spur soil degradation, loss of vegetation, biodiversity and permafrost, and increases in fire damage and coastal degradation.

Water will become more scarce, and our food supply will become less stable. Exactly how these risks will evolve will depend on population growth, consumption patterns and also how the global community responds.

Overall, proactive and informed management of our land (for food, water and biodiversity) will become increasingly important.

Source: The Conversation