It is not the drought as you know it. Scientists are saying so because they have found that it is not just about scarce water. They say that when the life sustaining liquid becomes quite scarce, plants find a way of surviving the extreme condition. And that is where the good news ends. The bad news is that when plants adapt to the harsh environment, they accumulate toxins to dangerous levels that can kill livestock and can cause cancer and other serious illnesses in humans.

How about heavy rainfall after a prolonged drought? If you thought it could be a respite for us all, you are in for a surprise. A new report has shown even drought-breaking intense rains can lead to accumulation of dangerous toxins in plants. Welcome to the world of extreme weathers and toxic crops.

70 percent toxic

That is the dire message the United Nations Environment Programme (UNEP) has delivered through a report released during its second general assembly this week. Scientists who wrote the report say extreme weather conditions and rising temperatures will make 70 percent of the world’s agricultural production toxic to animals and humans across the globe.

Such toxins include nitrate and prussic acid. The first one gets accumulated in crops like wheat, barley maize, millet, soybean, among others, because of acute droughts, the UNEP report says. The second one gets deposited in crops such as flax, maize, coffee, cherries, apples, among others, as a result of heavy rainfall after prolonged dryness.

In normal conditions, plants can turn nitrates into protein. But during extreme weather conditions, they cannot complete that process and the chemicals accumulate.

Several research before the UNEP report had found that nitrate and prussic acid poisoning occurs when cattle eat forage stressed by severe environmental conditions. The toxin converts the oxygen-carrying haemoglobin in the blood to methemoglobin which cannot carry the life supporting gas.  

Worse news for us

While that is already bad news for small scale farmers and herders, mainly in poor countries like Nepal, there is even worse news. The UNEP report has warned that over 4.5 billion people from the developing world are at risk of exposure to a particular highly harmful toxin in crops.

It is known as aflatoxin, one of the mycotoxins that are chemical by-products of fungal growth causing severe damage to the health of animals and humans even at small concentrations. Mycotoxins fungi infect many crops such as coffee, groundnut, maize, oilseeds, peanut, sorghum, tree nuts, and wheat.

“In many African and Central American countries, a subsistence farmer may eat 500 grams of maize per day,” Professor John Leslie of Kansas State University told me in an interview I did for the BBC. “They can easily be exposed to threatening levels of aflatoxin, even if the grain meets the safety standards set by the EU.” In Kenya, for instance, hundreds of human death cases were attributed to the consumption of aflatoxin contaminated maize products some years ago.

“That prompted the Kenyan government to condemn 2.3 million bags of maize,” agriculture scientist Jagger Harvey, one of the authors of the UNEP report, told the BBC. Scientists say mycotoxins including aflatoxins get accumulated in crops because of increasing temperatures. And now the toxin is expected to contaminate crops in higher latitude.

A study published in 2013 showed aflatoxins were found in maize grown in different regions of Serbia because of hot and dry weather with prolonged drought during the spring and summer of 2012. Another study said the contamination in maize could become a food security issue in Europe. But, as you can imagine, European agro scientists might find one or the other way to deal with the issue.

Even in Africa, research is gaining ground. “Initiatives like the Partnership for Aflatoxin Control in Africa have been established to work with policymakers and other key stakeholders on the African continent, to help them address this particular challenge in concert,” said Professor Harvey. “We are at a critical point where the risk for contamination is significant, and potentially expanding; and interventions are being developed, adapted and deployed to address this issue globally.”

Our food security

The question now is: Will Nepal be able to take advantage of such solutions? Before seeking an answer to that, you need to ask a more fundamental question: Does Nepal even know what is happening to its crops in the wake of extreme weather events?

Or, do we know what kind of crops we are importing if they are coming in from places that are prone to drought and intense rainfall? The UNEP report has pointed out there is no dearth of such places now. And as Professor Leslie said: Food security has both quantity and  quality aspects to it. “People need enough calories, but they also need to include essential nutrients and to exclude noxious contaminants such as disease-causing organisms and toxic chemicals.”

Khadka is a BBC journalist based in London