Climate change is making temperatures deadlier, food less reliable, experts warn

Oct 30, 2024

Climate change, driven by fossil fuel emissions, is raising temperatures to dangerous new heights, while also worsening drought and food security, a new report by doctors and health experts warned on Tuesday.

The record temperatures of 2023 - the hottest year on record - meant the average person experienced 50 more days of dangerous temperatures than they would have without climate change, according to the Lancet Countdown, an annual report based on work by dozens of experts, academic institutions, and U.N. agencies, including the World Health Organization.

Especially vulnerable are the elderly, with the number of heat-related deaths in people over 65 last year reaching a level 167% above the number of such deaths in the 1990s. Without climate change, researchers would have expected that number to rise by 65% from the 1990s, the report said.

"Year on year, the deaths directly associated with climate change are increasing," said Marina Belén Romanello, executive director of the Lancet Countdown.

"But heat is also affecting not just the mortality and increasing deaths, but also increasing the diseases and the pathologies associated with heat exposure," she said.

For example, people who exercise outdoors are increasingly at risk, she said. Companies are facing limited capacity for working outdoors.
In fact, last year's extreme heat cost the world an estimated 512 billion potential labor hours, worth hundreds of billions of dollars in potential income, the report said.

"Similar to what we saw with the COVID-19 pandemic, it is key workers who tend to be most exposed and unable to shield as easily during heatwaves, such as those working in one of our many hospitals without air conditioning, or outdoor construction workers," said data scientist Nathan Cheetham at King's College London in a statement. Cheetham was not involved in the study.
Climate change is also making food more unreliable, the authors warned.

With up to 48% of the world's land area facing extreme drought conditions last year, the researchers said, about 151 million more people would be experiencing food insecurity as a result, compared with the years 1981-2010.

Extreme rainfall last year also affected roughly 60% of lands, unleashing floods and raising risks from water contamination or infectious disease.

The study's authors urged the upcoming U.N. climate summit, COP29, to direct climate finance toward public health. The COP29 talks begin Nov. 11 in Baku, Azerbaijan.

U.N. Secretary-General Antonio Guterres on Tuesday called on countries to "cure the sickness of climate inaction" by slashing fossil fuel use and emissions in order "to create a fairer, safer, and healthier future for all."

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Video: Turning Plant Defense Into a Management Strategy

Turning Plant Defense Into a Management Strategy

Understanding how a plant responds to stress is one thing.

Using that knowledge to make better management decisions is another.

Systemic acquired resistance, or SAR, is the plant's more direct defense response. When stress or infection occurs, the plant begins signaling throughout its system and preparing defensive compounds.

But if we know that response exists, can we help prepare the plant before the stress arrives?

The answer starts with understanding what triggers the response and what the plant needs to carry it out.

The Trigger and the Fuel

Salicylic acid plays an important role in triggering the SAR pathway.

Think of it as turning the truck on.

The engine may be running, but it still needs fuel to do the work.

In this case, manganese plays an important role in supporting the enzyme systems involved in the plant's defensive response.

This makes manganese status an important part of the conversation. Whether a producer is using tissue testing, sap analysis, or simply scouting for visible deficiency symptoms, the goal is to make sure the plant has adequate manganese available.

Manganese is required in relatively small amounts, but that does not make its role small.

If the plant receives a signal to defend itself but lacks the nutrition needed to support that response, it may struggle to carry out the process efficiently.

The trigger matters.

The fuel matters too.

Prepare Before the Stress Arrives

The best time to think about stress management is before the plant is overwhelmed.

Once a crop is already struggling, management can quickly turn into a game of catch-up.

This is similar to nitrogen management. Once a plant becomes severely deficient, correcting the problem does not necessarily erase the time and yield potential already lost.

Plant defense can work the same way.

Low-rate, targeted approaches designed to support the SAR pathway may fit best ahead of an expected stress event rather than after significant damage has already occurred.

That requires producers to think about predictable stress.

We may not know exactly what the weather will do tomorrow, but we generally know summer heat is coming. We know certain field conditions increase disease pressure. We know a herbicide application can temporarily stress a crop as the plant processes the chemistry.

Even a properly timed and labeled herbicide application can create a temporary response in the plant.

That does not mean the herbicide is bad.

Weeds can create significantly more yield loss than the temporary stress caused by controlling them.

The question is not whether we should eliminate every stressor.

The question is whether we can better prepare the plant to manage necessary and predictable stress.

Not All Stress Is Bad

Stress is a normal part of plant growth.

A perfectly stress-free environment does not exist in the field.

In fact, some stress is necessary for normal plant development. A plant responds to wind, temperature, moisture, sunlight, and countless other environmental signals throughout the season.

The environment is stress.

The plant's job is to manage it.

Problems begin when the stress load becomes greater than the plant's ability to respond.

Extreme heat, drought, high salt concentrations, disease pressure, and even certain management practices can add to that load.

This is where understanding SAR becomes useful.

Instead of waiting until the plant is visibly struggling, producers can begin identifying periods when stress is likely and make management decisions around those windows.

ISR Starts With the Soil

While SAR is a more direct defense response, induced systemic resistance, or ISR, brings the conversation back to soil health.

The longevity of a farm is closely connected to the health of its soil.

Carbon plays a major role because it supports biological life within the soil. Bacteria, fungi, and other organisms interact with plant roots and influence how the plant grows, accesses nutrients, and prepares for stress.

This is why soil health cannot be reduced to one product or one application.

It is a system.

Keeping living plants in the field longer can support biological activity. Cover crops may fit some operations. Better water management can improve soil conditions.