Hotter, colder, fewer steaks: 11 things to know about our new world


Hotter, colder, fewer steaks: 11 things to know about our new world

The World Meteorological Organisation has declared the first week of July the hottest yet recorded in the northern hemisphere, while Joburg has had snow for the first time in 12 years. ANNELIESE BURGESS speaks to Prof Peter Johnston from UCT's Climate Systems Analysis Group about extreme weather patterns all over the world.


1. A double whammy

Let's first understand how natural seasonal variability causes some summers to be hotter than others and some winters to be colder or warmer.

The El Niño-Southern Oscillation (ENSO) is one of the most important climate phenomena due to its ability to change the global atmospheric circulation, which influences temperature and rainfall. El Niño and La Niña are the two extreme phases of the ENSO cycle.

El Niños are when winds blow across the Pacific Ocean and bring warm water to the surface. We are not sure what circumstances lead to these winds, but we know that warm water results in warm air, and that changes wind and pressure systems. Ultimately, the Earth gets warmer during an El Niño because heat is released from the oceans. That heat was absorbed by the oceans gradually over the years, and when it is suddenly released it affects temperatures worldwide. 

When El Niños happens in the northern hemisphere, where most land is situated, you feel the heat because the land absorbs it and radiates it again. During El Niño, which is where we are heading, areas in the northern hemisphere that have summer will experience hotter conditions.

Now, it's still the beginning of El Niño, so that doesn't explain everything. What is exacerbating the situation is that we are getting this on top of a global warming signal, which means the Earth is warming inexorably. Since 1900, at least, we've seen the temperature increase. Not every year necessarily, but every decade is warmer than the last. 

We're seeing record summer temperatures in many places but El Niño hasn't yet reached its full strength. That will happen in October, November and December when our summer comes along, so we can expect hotter temperatures than in a normal year. This double whammy is where the danger lies.

Peter Johnston
Peter Johnston

2. The knock-on effect

These record temperatures in the north cause a complex arrangement of things that one cannot say are directly attributable to global warming, yet there is attribution.

The extreme heat causes fires and air pollution. And global warming affects things like kelp, crop damage, water shortages and even sewerage. We have been talking about these things for years. People argue they are not connected to global warming. But in a year as extreme as this one we are seeing these problems surface, and they would not have surfaced if there was no global warming. 

3. Global warming also causes cold

If you look at the cold weather we've been having, there are similar reasons.

Natural variability always causes warmer or colder winters, but the Western Cape has had the highest rainfall this year since the 1970s. That comes from cold fronts caused by cold air from the polar regions interacting with warmer air. This causes condensation and precipitation and causes cold fronts which bring us rain. We've had a high frequency of those in the Western Cape. 

While the rain falls mainly in the Western Cape, the cold pushes up into the interior, which can cause the snowfalls we've seen in Johannesburg, for instance.

Why is there so much cold air if we have global warming? Well, global warming is causing the ice to melt, and the ice is going into the oceans and cooling them. So there's a lot more cold water, and therefore cold air. And this happens in the northern hemisphere as well. We had icy winters in North America and Siberia a couple of years ago.

So there's the story of the hot and the cold, and it scares us scientists. 

4. Weather is unpredictable

Weather has always been hard to predict. Occasionally, we have a signal like the Niños, which we know will probably cause a warmer-than-normal summer, or usually a drier-than-normal summer. This is what we can expect this coming year in our summer rainfall areas.

Extreme events are even harder to predict, and we are seeing them happen more and more often. 

The frequency of El Niños is also unpredictable. We had three La Niñas in a row in 2021, 2022, going into 2023. They caused above-average rainfall, and summer rainfall regions are now wetter than they have been for a long time. 

But we are now heading into El Niño, which means drier conditions, and we don't know how often that's going to happen. We watch El Niño to see whether it's strengthening or weakening. That we can predict, but not with absolute certainty.

5. We have to adapt to uncertainty

We don't know how global warming will affect different locations or what hidden feedback systems or impacts there will be. We also don't know how much global warming will increase or decrease in the future.

Global warming leads to a more active atmosphere and more extreme events. For example, we have hail in places we haven't seen hail beforem and that affects our fruit farmers.

We try to run models and work out mitigation plans for what is coming, and we call that adaptation. Farmers may buy nets to protect their crops from extreme sunlight or hail. Or they'll look at alternative crops or  farming methods, or alternative areas and markets. This is all part of the adaptation scenario.

6. We have to plan for the fallout 

We must do things differently to reduce global warming. That's called mitigation. We need to change the way we produce electricity. We need reduce our use fossil fuels and reduce the amount of plastic we make. 

There are policies, COPS [conferences of the parties] and various government initiatives to reduce emissions and set targets. But as scientists we can see that politicians aren't completely committed and change will have to come from private systems. That is why we see people putting up solar systems without government help. We see businesses making plans for what they see in the future.

Some governments are on board. But Africa says, “why should we do it if the Western world was built on hundreds of years of burning coal and doing things to pollute the atmosphere, and now we must pay for that?" These are ethical and moral issues that we have to look at, but they make it very uncertain that we will reduce emissions.

7. Scientists are planning for the worst

We are hoping for the best but planning for the worst. The first step is to identify the hazards, then you ask whether you are vulnerable to these things. 

A simple example: if you are sitting in an old age home in Postmasburg  where it gets to 40°C and there's no air-conditioning, you are far more vulnerable than someone sitting in an air-conditioned retirement home in Constantia. It won't get that hot in Cape Town, but in the Northern Cape it will get tricky. For farmers, the question is whether their crops are vulnerable to changing conditions.

Take maize farming. There's a very tight threshold of viability around an average of 26-27°C. If the average temperature goes over that consistently, you can't plant maize any more. And regarding rising temperatures, certain places in South Africa will become unlivable.

We must work out how to respond to our vulnerability to these threats, and that is complicated because there isn't a single answer. But we will not survive if we do not respond.

This is a very heavy subject, and human nature means you only really think about it when you get hot. You hear people making jokes about the cold. “I would love to have some global warming. Where is global warming when you need it?" Like Donald Trump. And that's just stupid. 

8. Water is a burning issue

We don't know exactly what will happen to water except that it will evaporate faster. Droughts, when they come, are going to be worse.

All the Mediterranean regions in the world will become susceptible to water shortages. Whether it's the Western Cape, South Australia, the west coast of South America, California or the actual Mediterranean regions, they will be heavily affected by these water shortages and increases in temperature.

When it comes to the rest of our country, it's mainly the heat and the susceptibility to drought.

It's going to make life very hard.

9. About polar ice 

Polar ice melting is a canary in the coal mine because it is real evidence of warming. The Arctic ice cap melting has no impact on sea level as it's floating ice. But Antarctic ice is on land, and that melting does contribute. If just one-tenth of Antarctic ice melts, sea levels will rise by around 10m. This will inundate most coastal cities, including Cape Town.

But there are other impacts too. Polar ice waxes and wanes with the seasons but it is continually diminishing. If the Arctic ice melts, it opens up the area for direct shipping between Europe and the Far East, and for mining. Both will have impacts on the South African economy.

10. Individuals can help

The very least every individual can do is to be part of the solution. Conserve energy. Drive less. Look at alternative energy sources.

Eating meat is a greenhouse gas contributor, but animals play a key role in the ecosystem, so it's about eating better and more sustainable meat and less of it. Air travel is contentious as it is a major contributor to the economy, and many people have family spread around the world. Reduce short trips, yes, take trains where possible, and fly economy class. 

But the big picture lies elsewhere.

11. The big picture is about governments

The big picture is how we can push governments to make decisions about emissions, and that's what environmental groups and others are working on — trying to change the minds of the Gwede Mantashes of this world and saying coal is an option for us but we must look at alternatives.

We get about 10% of our energy from solar, but by now it should have been at least 40%. We are very late to the party. We should have been investing in other viable options instead of new coal. Look at the way coal is sucking the lifeblood out of the economy because of corruption. It's also harming air quality and water quality. 

It's complicated, because to lobby politicians or your pension fund to get out of coal or oil companies and to invest in solar is hard work. But that is where people can make a difference

Put pressure on the government. Vote for a different party. Look at the manifestos. If the ANC is wedded to coal, then nobody should vote for them. They say they are protecting the workers, but nobody wants to be a coal miner. Nobody does that for fun.

Yes, of course, Africa needs lots of jobs, and a just transition means we must look for other jobs for coal miners. But if we start investing in alternative energy, if we start giving free training programmes for solar panel installers, and investment opportunities for people who want to make solar panels in this country, not in China, then we're on the right track.

I'm being simplistic here. Obviously, it's more complicated because you've got labour unions, and politicians, and investments, you've got crime, you've got load-shedding. No one said we have a shortage of issues in this country. But we must look at the opportunities and the possibilities.

We must be part of the solution. But right now, South Africa is part of the problem.

♦ VWB ♦

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