Every year the World Metrological Organization (WMO) publishes a range of reports examining the latest evidence on different meteorological and climatological factors. This year, a group of international specialists has produced a report specifically focusing on the State of the Climate in Africa, providing a snapshot of climate trends, observed high-impact events and associated risks and impacts in key sensitive sectors.
The Met Office was part of this group with scientists providing information on observed temperatures and detail on projections of what we could see in Africa in the future.
John Kennedy, who works on climate monitoring at the Met Office, was involved in the development of the report:
Africa is a hugely diverse continent, with vastly different landscapes ranging from rainforests to savannahs and deserts. As we are seeing in other parts of the world, temperatures in Africa have been rising in recent decades. 2019 was most likely the third warmest year on record for the continent, behind 2010 and 2016. As a continent, Africa was between 0.56°C and 0.63°C above its long-term average (1981-2010) temperature in 2019. Some individual countries including South Africa and Namibia saw 2019 temperatures locally exceeding 2°C above average.
As well as rising heat, Africa was affected by numerous extreme weather events in 2019, including Tropical Cyclone Idai, which was among the most destructive tropical cyclones ever recorded in the southern hemisphere with over 1,200 associated deaths in Mozambique, Zimbabwe and Malawi.
Most areas of Africa, covering a wide range of climate zones, saw above average temperatures in 2019, but rainfall patterns were much more variable. In 2019, in Southern Africa severe drought affected many areas which had already suffered a prolonged drought from 2014 to 2016. Meanwhile, in the Greater Horn of Africa, conditions shifted from very dry in 2018 and the start of 2019 to floods and landslides associated with heavy rainfall in late 2019. Flooding also affected the Sahel and surrounding areas from May to October 2019.
While extreme events often depend on the chaotic whims of the weather, considered over longer periods – months, years, decades – we can discern patterns that allow us to understand and, in some cases, to predict them. While individual events can be forecast reliably only days in advance, long-term drivers can shift the odds of such events happening in a predictable way. The strong positive phase of the Indian Ocean Dipole was one such driver associated with the extreme rainfall in Eastern Africa late in 2019. As we look back over the past decades, the warming signal from increased greenhouse gases in the atmosphere is increasingly clear.
As climate change continues to influence our weather and climate extremes, to make sure we can make accurate projections for what sort of extremes we might see in the future it is vital to start any kind of research with an accurate foundation understanding of the area. To help with this, last year an international collaboration of scientists led by the Met Office developed the first convective-permitting regional climate model, known as CP4-Africa. This model enables scientists to look at much finer detail the kinds of rainfall extremes Africa could experience as our climate warms.
Lead author of the first paper on future climate change from the CP4-Africa simulations, Dr Elizabeth Kendon of the Met Office, explains that, “Very high resolution climate projections provide a glimpse into future weather and climate extremes over Africa. CP4-A suggests that over the Sahel and east Africa extreme heavy rainfall events that occur about once every 30 years now, may occur once every 3-4 years by the end of the century if emissions continue to rise throughout the 21st century under a high emissions scenario.
“Dry spells during the wet season exceeding 10 days in length are almost twice as frequent in the future compared to the present-day over parts of central and western Africa: a signal which is not seen in a coarser resolution 25km model.”
It is well understood that Africa’s population and landscapes are vulnerable to extreme weather events. It is therefore important that we use our understanding to help those vulnerable communities prepare and adapt for future challenges as our climate changes.
Helen Bye is the Met Office’s Head of International Development and Principal Adviser to the Foreign, Commonwealth and Development Office (FCDO):
As detailed in the WMO 2019 State of the Climate in Africa report, Africa is vulnerable to the impacts of climate variability and change. Continuing to conduct climate research and improving climate modelling for the continent is vital to ensure the best possible understanding of the challenges ahead, in order to mitigate against and adapt to the impacts of climate change. This report also made reference to the need to strengthen multi-hazard early warning systems (MHEWS) and build capacity in the provision of climate services in Africa, and the WMO 2020 State of Climate Services report echoed this. According to the latest report, over the last 50 years 35% of deaths related to weather, climate and water extremes occurred in Africa and yet the continent has one of the weakest capacities in MHEWS.
At the Met Office we work with our global partnerships to help build capacity in weather and climate services, including in Africa. Those partnerships involve many and varied organisations, from the WMO, national and regional meteorological services, to non-governmental organisations, United Nations bodies and community initiatives. Critically our international development work takes a people-led approach, ensuring that the capacity building process is built around the needs of the users of weather and climate information.
The Risk-Informed Early Action Partnership, of which the Met Office is a founding member, contributed to the WMO 2020 State of Climate Services report and is an example of the global collaboration needed to bring about significant change. The partnership aims to make 1 billion people safer from weather and climate-related disasters by expanding early action financing and improving climate information and early warning systems and the capacity to act on the risks they identify.
One example of the benefits of MHEWS highlighted in the WMO 2020 State of Climate Services report (page 35) is on the Weather and Climate Information Services for Africa (WISER) HIGHWAY project, funded by the FCDO. Led by the WMO with partners including the Met Office, this project worked with the national meteorological services of countries bordering Lake Victoria to develop a regional Early Warning System (EWS). 3000 to 5000 deaths occur in the Lake Victoria Basin every year due to navigation accidents caused by strong winds and high waves also tragically resulting in loss of livelihood for their dependents. Data from the project suggests that there has been an approximately 30% reduction in deaths since the introduction of the EWS. You can learn more in this BBC World Service podcast (8:45-15:05).
The local challenges faced on Lake Victoria led to the development of this EWS, and the people-led approach I mentioned along with an understanding of the risk factors is key to improving or developing new weather and climate services in Africa. Different African countries and regions face different weather and climate challenges, so the weather and climate community and partners need to continue to translate robust science into relevant and timely services which enable people to take action to stay safe and thrive.