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Apart from the general higher temperatures, global warming creates two additional problems for Zimbabwe: A higher likelihood of drought each year and a higher likelihood of more cyclones blowing in from India Ocean.
Many of our droughts are caused by El Nino events in Pacific Ocean. The weather patterns created by the accumulation of warmer water west of the central Pacific sloshes back, creating wind patterns that bring more rainfall to certain parts of the globe, such as Southern Africa.
Some have also linked global warming to the trend towards later rainy seasons. However, even in good years, we now see rains begin later than our parents used to remember. This presents its own problems.
As the world gets warmer, tropical cyclones and tropical storms will become more common.
They absorb the energy from the ocean and the warmer the water, the more energy they will gain and the more water they can absorb.
Higher winds mean more energy, and more water must be absorbed to ensure that more rain falls when it is released. A warmer ocean can lead to more minor depressions, which can then become cyclones.
The bottom line is that we will experience more cyclones every season, that these will tend to be more destructive and that they will bring in more rain.
One tropical depression has already entered Zimbabwe during the cyclone season in south-west Indian Ocean. We can expect six more to cross our borders.
Although the Meteorological Services Department can forecast the averages and other factors, it cannot predict the intensity of the rain or how much they will bring.
Some of the cyclones over the ocean may miss Zimbabwe, like Cyclone Batsirai last week. There are more than seven cyclones that cause depressions each season, but our statistics show that there are fewer because some don’t get as far as Zimbabwe.
Cyclone Idai was the ninth season’s storm for those who count.
We must be able track the progress of cyclones to make better predictions about how much rain they may dump on Zimbabwe, and how strong the winds might become.
Satellite imagery can be very useful for the Met Department to monitor and track the course of a storm, but it does not measure all its properties.
This is already happening in the country, or in the case with the weather radars, it is on the horizon as both the Government and the development partners make efforts to ensure that our weather experts have the tools they need.
July Moyo, Ministry of Local Government and Public Works, observed this week, when accepting the first batches of new equipment, that if we have the right warnings and have the right plans, we might be able to prevent cyclone deaths but not cyclone damage.
This is not an unreasonable goal.
It is crucial to ensure that warnings are sent to the right areas at the right time. It is difficult to know what level alert to give.
After Cyclone Idai, we created sets of plans.
Although the low-energy tropical storm and subsequent depressions did not require evacuation, the alert system was able to reach all affected areas.
We saw roof damage and other damage, but no one was hurt.
As we face more drought and more cyclones, the other policy we must pursue is more dams.
If we see an increasing amount of our annual rainfall coming with storms, cyclones and depressions, then we will get more rain in fewer days. So we need to be able to store what comes.
The Second Republic already upgraded our dam construction program, and now it needs to take it further.
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These models have been in use for a long time by water engineers.
The designer of Lake Mutirikwi, built decades ago, was ridiculed for his design choices over the years. The dam never filled for a while.
He was finally vindicated after one of these major hurricanes passed over the Lowveld. The dam was quickly filled. He had intended to capture the Lowveld’s cyclonic rainfall and store it for many years.
It is important to apply the same planning and attitude to other dam sites.
This means that the cyclones can be used to alleviate the other side-effects caused by climate change, droughts. It also means that more farmers will have access to supplementary irrigation at season’s beginning to ensure that crops are established before the main rainfalls fall.
In other words, applied science can help to prevent some of the worst effects from climate change by being better equipped to predict what will happen and monitor what is actually occurring. Engineering can also help us to use one set effect to beat another.
