What the latest assessment on global warming means for southern Africa

The Special Report examines the growing impacts of climate change worldwide. For "hot spots" of climate change – hot, dry and water-stressed countries like Botswana and Namibia in southern Africa – local warming and drying will be above the global average.

The report highlights the urgent need for countries such as Botswana and Namibia to prepare and adapt quickly. The goal of the Paris Agreement, which is to limit global warming to well below 2 ° C, ideally 1.5 ° C, at the beginning of the century, will be extremely difficult. To date, countries' mitigation commitments are well below global warming requirements of 3.2 ° C by 2100. With an increasing emission trajectory, the 1.5 ° C threshold could be exceeded in the next decade, and the 2 ° C mark the next decade.

Our analysis of the effect in Botswana and Namibia of 1.5 ° C, 2.0 ° C and higher levels of global warming shows that it is likely that they become more hot, drier and more stressed by water. The sooner the countries of southern Africa prepare and implement adaptation strategies, the better.

Impact

Botswana and Namibia are already experiencing the challenges of drought and floods. A few years ago, Gaborone, the capital of Botswana, was on the verge of running out of water as the country went through its worst drought in 30 years. Neighboring Namibia has faced recurring and devastating droughts and floods in recent years, particularly in the northern areas where most of the population lives.

A global warming of 1.5 ° C would lead to an average temperature rise from the pre-industrial base of 2.2 ° C in Botswana and 2.0 ° C in Namibia. With a global warming of 2.0 ° C, Botswana would undergo a warming of 2.8 ° C. Namibia would heat 2.7 ° C.

Changes in precipitation are also expected to change. At 1.5 ° C from global warming, Botswana would have 5% less annual rainfall and Namibia 4% less. At 2.0 ° C, annual precipitation in Botswana would fall by 9%, while annual rainfall in Namibia would decrease by 7%.

Both countries would also see an increase in dry days. At a global warming of 1.5 ° C, projections show that Botswana still has 10 dry days a year. This number rises to 17 days without additional rain with a global warming of 2.0 ° C. In Namibia, dry days increase by 12 when global warming is 1.5 ° C and from 17 to 2.0 ° C.

The impact of global warming on extreme events is also evident. Both countries can expect about 50 more days of heatwaves to heat up to 1.5 ° C and about another 75 days of heat to a warming of 2.0 ° C.

The tables show the expected impact of warmer temperatures.

Vulnerable sectors

The effects of rising global and local temperatures will be felt in various sectors essential to the prosperity of the populations and economies of both countries.

Understanding what this will mean for sectors such as agriculture, health and water, is crucial for planning adaptation and thinking about what needs to be done and in what timeframe.

In a warmer and drier future, there will be less domestic water available. Runoff in the Botswana Limpopo Basin is expected to decrease by 26% to 1.5% from global warming and by 36% to 2.0%. In Namibia, evapotranspiration rates increase by 10% to 1.5% of global warming and by 13% to 2.0%, resulting in reduced river flows and drier soils.

Agriculture is particularly vulnerable, with potential decreases in yields and an increase in livestock losses. In Botswana, at 1.5, corn yields could fall by more than 20%. At 2.0 warming, yields could fall by 35%. Rainfed agriculture is already marginal in much of the country, and anticipated climate change could make current agricultural practices unsustainable at 1.5 and above. In Namibia, cereal crop productivity is expected to fall by 5% to 1.5 and by 10% to 2.0.

The impacts of global warming on human health are also essential to take into account. Thermal stress should become a bigger threat. With 1.5 of global warming, Namibia and Botswana can expect approximately 20 additional days of heat stress exposure in one year. At 2.0, in Namibia, this doubles about 40 additional days of exposure to heat stress.

All of these factors become even more serious if the 2.0 threshold is exceeded.

Urgent action is needed

Increasingly severe climate impacts of 1.5 and 2.0 ℃ in these countries require concerted action at the local and international levels. Leaders from countries such as Botswana and Namibia can not let go on the world stage to urge nation-states to hold and further improve their commitment to reduce greenhouse gas emissions in accordance with the Agreement from Paris. As the IPCC report shows, quick and decisive action will not only reduce the risks of exceeding Paris' temperature targets, but also the rate of change, thus facilitating the deployment of local adaptation.

At the same time, highly exposed countries such as Namibia and Botswana need to anticipate and plan for fairly rapid changes in local weather and climate. They need an acceleration in developing coping strategies in a way that works for everyone and across the economies of those countries. The time for adaptation projects and pilot experiments is over and the time to start integrating climate resilience into the public, private and community sectors has come.

At the same time, governments, scientists and development practitioners need to think in the longer term and think about what it means beyond the 1.5 ° C and 2 ° C targets for adaptation. At some point, the adaptation of these systems may not be sufficient and complete transformations into new livelihoods suitable for a world above 2 ° C may be necessary.

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