Botswana, Namibia hotspots

WARMING: COUNTRIES CAN EXPECT TO BE DRIER AND HOTTER – REPORT

Warning to act soon – or suffer devastating consequences.

The release this week of the Intergovernmental Panel on Climate Change’s (IPCC) special report on global warming of 1.50C above pre-industrial levels marks a critical point in climate negotiations. The report illustrates how crossing the ever-nearer threshold of 1.50C warming will affect the planet, and how difficult it will be to avoid overshooting this target.

It takes a worldwide look at the growing impacts of climate change. For climate change “hotspots” – hot, dry and water-stressed countries like Botswana and Namibia in southern Africa – local warming and drying will be greater than the global average.

The report underscores the urgent need for countries like Botswana and Namibia to prepare and adapt – and do so quickly.

The Paris Agreement’s goal of limiting global warming to well below 2°C, ideally 1.5°C, by the turn of the century will be extremely challenging. To date, mitigation pledges by nations fall far short of what is needed, with global temperatures on track for a warming of 3.2°C by 2100.

Under an increasing emissions trajectory, the 1.5°C threshold could be breached as early as the next decade, and the 2°C mark the decade after.

An analysis of the effect in Botswana and Namibia of 1.5°C, 2°C shows they’re likely to get hotter, drier and more water-stressed. The sooner southern African countries prepare and implement adaptation strategies the better.

Botswana and Namibia already know the challenges of droughts and floods. A few years ago, Botswana’s capital city, Gaborone, was on the brink of running out of water as the country battled its worst drought in 30 years.

Neighbouring Namibia has battled with recurring and devastating droughts in recent years, especially in its northern regions, where most of the population live.

Global warming of 1.5°C would lead to an average temperature rise above the pre-industrial baseline in Botswana of 2.2°C, and Namibia 2°C. At 2°C global warming, Botswana would experience warming of 2.8°C. Namibia would warm by 2.7°C.

Changes in rainfall are also projected to shift. At 1.5°C of global warming, Botswana would receive 5% less annual rainfall, and Namibia 4% less. At 2°C global warming, annual rainfall in Botswana would drop by 9%, with annual rainfall in Namibia dropping by 7%.

Both countries would also see an increase in dry days. At global warming of 1.5°C, projections show Botswana having 10 more dry days per year. That number rises to 17 extra dry days at 2°C global warming. For Namibia, dry days increase by 12 at global warming of 1.5°C, and by 17 at 2°C.

The impact of global warming on extreme events is also evident. Both countries can expect roughly 50 more days of heatwaves at 1.5°C global warming, and about 75 more days at 2°C.

In a hotter, drier future there will be less domestic water available. Runoff in Botswana’s Limpopo catchment is projected to decline by 26% at 1.50C global warming, and by 36% at 20C.

In Namibia, evapotranspiration rates increase by 10% at 1.50C global warming and by 13% at 20C, leading to reduced river flows and drier soils.

Agriculture is particularly vulnerable, with potential drops in crop yields and increased livestock losses. In Botswana, at 1.50C global warming maize yields could drop by over 20%. At 20C warming, yields could slump by 35%. Rain-fed agriculture is already marginal across much of the country, and anticipated climate change may well make current agricultural practices unviable.

In Namibia, productivity of cereal crops is expected to drop by 5% at 1.50C and 10% at 20C.

The impacts of global warming on human health are also essential to consider. Heat stress is projected to become an increasingly greater threat. At 1.50C of global warming, Namibia and Botswana can expect roughly 20 more days of heat stress exposure in a year. At 20C, in Namibia this doubles to around 40 more days.

All of these factors become even more severe should the 20C threshold be overshot.

The progressively serious climate impacts at 1.50C and 20C in these countries demands concerted action, both locally and internationally.

Leaders from countries such as Botswana and Namibia cannot let-up on the global stage in pushing for nation states to improve their pledges to cut greenhouse gas emissions in line with the Paris Agreement.

As the IPCC report shows, early action will not only reduce the risks of overshooting the Paris targets, but also slow down the rates of change, making local adaptation easier to roll out.

This article was first published in The Conversation.com