Chocolate has a climate change problem. Last week, cocoa prices rose to all-time highs on commodity exchanges in London and New York, reaching more than $10,000 a tonne. After the third successive bad harvest in west Africa, there is a global shortage of the cacao seeds that are used to make chocolate – and the situation may not improve quickly.

After a weekend break feasting on Easter eggs and bunnies, chocolate may be the last thing on your mind, but the broader question about how rising temperatures will affect global food supplies is not going away.

More after this week’s most important reads.

Olive oil, coffee and even potatoes are among the dozens of crops also facing serious climate risks. Scientists have previously said that global heating drives a higher risk of simultaneous harvest failures across major crop-producing regions, threatening global food security. Researchers are scouring the planet for hardier varieties of common staples.

The reasons for surging cocoa prices are complicated. The poor harvest has been driven by a mixture of underinvestment in ageing cacao plantations, poor planning and speculators, say experts, along with extreme weather supercharged by global heating. Last month, the World Weather Attribution confirmed that a February heatwave was made 4C hotter and 10 times more likely by human-caused global heating.

Chocolate will not run out – despite admissions from major brands that bars are likely to shrink alongside price rises – but it is an early sign of what may await us as temperatures rise and food production becomes less predictable.

To understand what is going on with the so-called “chocolate meltdown”, I spoke with Martijn Bron, a former head of cocoa trading for the commodity giant Cargill, about the reasons behind the huge spike in prices.

“There is a large shortage of fresh cacao beans. Normally there is a global crop of about 5m tonnes. Now it’s about 0.5m tonnes less,” said Bron. “The market is nervous about whether these issues are a one-off perfect storm or something structural. If it is structural, this is a problem because it means you cannot easily do something about it and it may take much more time to recover, maybe five plus years.

“One of the reasons why there is a deficit is ageing trees. What is the problem with ageing trees? Well, after about 20 years, the yield on cacao trees starts to go down. All the time you need to be planting new cacao trees in order to maintain your maximum yield and this hasn’t been done.”

Higher prices could be good for farmers in the medium term as it may result in much needed investment in the sector, explained Bron, adding that prices were unlikely to fall soon. The cacao industry has long had problems with child labour and many farmers have been unable to afford to improve their climate resilience. This may be the opportunity to do so.

Read more:

The good news

The bad news

Down to Earth readers on the eco-friendly changes they made for the planet

Australian reader Sheri Adams emailed to tell us about her ambitious, life-changing move: building a home from scratch, designed around the environment.

“Nearly every home we have lived in has been hot in summer, cold and drafty in winter, and expensive to run,” says Adams. “This time we wanted to live in a home which was none of those things.”

After a two-year build, Adams’ home now has “solar panels with battery storage, double glazing, top-rated insulation in ceiling and walls, good ventilation, orientation, hydronic underfloor heating, some thermal mass floors and walls, fans, very low VOC paint and rainwater for use in the home and garden.”

Let us know the positive change you’ve made in your life by replying to this newsletter, or emailing us on downtoearth@theguardian.com

Profiling the Earth’s most at-risk animals

Population: Unknown
Location: Worldwide
Status: Endangered

The largest of tuna species, they live for up to 40 years, dive deeper than 3,000ft and are made for speed – their bodies torpedoing vast distances across the ocean. Overfishing and the climate crisis have seen populations rapidly decline, but Atlantic populations are on the rise following a fishery management programme.

For more on wildlife at threat, visit the Age of Extinction page here

One image that sums up the week in environmental news

Credit: Dr Jane Goodall/Courtesy of Vital Impacts

Ninety female landscape and wildlife photographers have come together for a unique project celebrating the 90th birthday of the anthropologist Dr Jane Goodall. Above is a contribution from the star of the show herself: a self-portrait taken in the Gombe national park in Tanzania.

“I was on my own, very high up in the hills and I thought what a great photo this would make,” says Goodall. “I had to set up the tripod and fiddle about until I had the tripod and the imagined image of me framed just right. That was in the days before digital so I had to wait a long time before I got the results back from National Geographic. I was pretty proud of myself.”

For more of the week’s best environmental pictures, catch up on The Week in Wildlife here