Future Climate Projections for Malawi

Published: 16th February 2018 18:24Last Updated: 14th June 2018 16:33
malawi climate change

Introduction

This brief* provides an overview of future climate change in Malawi, using results from the latest available climate model simulations. The UMFULA research team of the Future Climate for Africa (FCFA) programme has analysed 34 Global Climate Models (GCMs) that provide projections for Malawi to try to distil robust messages and some key trends that may help planning and decision-making.

The brief first presents a summary of recent observed rainfall and temperature variability. This is followed by an overview of the range of climate projections available from the leading source of climate model results. A detailed annex (available from the Further Resources section, below) describes the methods and datasets used in the brief and presents a wider range of figures for further reference. A two-page summary also highlights key findings (see Further Resources).

This brief is not comprehensive and neither is it the only source of climate model results. It serves as an introduction to non-expert audiences with an interest or need to consider climate change in Tanzania. This brief complements the FCFA Guide: How to understand and interpret global climate model results

*Download the full report from the right-hand column. The text belwo provides key points only; see the full text for much more detail.

Key findings

Recent trends

  • Annual temperatures are increasing (warming is occurring).
  • There is a lot of variability in rainfall amounts and seasonality (i.e. when the rain falls), but there is an overall drying throughout the country.
  • Moderate wetting trends can be seen in central and northern parts of Malawi.

Future climate

1. Temperature

  • In temperature, there is strong agreement between the models, implying that these are robust projections.
  • By the 2040s, we see warming throughout the country, from 0.5-1.5°C. By the 2090s, we see a stronger projected trend for warming, from 4-4.3°C (Figure 1).
  • Other things being equal, warmer temperatures are likely to increase evaporation from soil and open water.

Summary of climate changes in Malawi (figure 1 of the report).

2. Rainfall

  • In terms of annual total rainfall, the models are highly varied (Figure 2). Out of 34 models, almost half show that changes in rainfall are likely to be less than 5%, whilst the rest disagree on whether it will be wetter or drier – this means there is lower confidence in projections of future rainfall changes.
  • Malawi’s climate is diverse, with the country divided into two main climatic zones that experience different rainfall seasons. Country-wide averages disguise this geographical variation.
  • Taking an average of the 34 models, there are small changes by the 2040s. Stronger trends are observed if we look at seasons.

3. Extreme events

  • As climate evolves we will see an overall increase in the frequency and intensity of heatwaves. All models show an increase in the number of days with temperatures above 30°C (a threshold sometimes used to examine the sensitivity of maize to heat stress).
  • For rainfall there is strong agreement for decreases in the mean number of rain days and increases in the amount of rainfall on each rainy day (the ‘rainfall intensity’).
  • Taken together these changes suggest more variable rainfall, with both higher likelihood of dry spells and higher likelihood of intense rainfall events (often associated with flooding).

Proportions of climate models projecting small changes (less than 5%), drier and wetter conditions across Malawi (figure 2 of the report).

Outcomes and Impacts

  • Climate projections are useful to consider in planning, particularly for activities that are sensitive to temperature and water availability, such as agriculture and hydropower.
  • The high level of agreement between models on temperature increase means there is confidence in this projection.
    • This has implications for planning. For example, promoting a crop that is heat sensitive and already near the margins of tolerance for growth is likely to be unsustainable in the long run.
  • There is less agreement between models on rainfall, but there are some indications (low confidence) for a drying trend in September-October-November throughout Malawi – a critical time, for example, for the agricultural sector.
    • Awareness of this means that longer-term agricultural decisions can be planned accordingly to avoid crop failure due to delay in the start of rains during November.