That's proper, our world is made of knowledge, local weather change is rising crop yields, fears of future declines are unfounded – do you agree?

From the climateREALISM

By H. Sterling Burnett

Our World In Data (OWID) published a series of articles by Hannah Ritchie examining the impact of climate change on crop production. Overall, the reports set the record straight and indicate that yields of key staple crops have increased dramatically, in large part due to the CO2 fertilization effect and slightly warmer temperatures; However, parts of the stories stray into speculation that some crops have grown less than expected and that they will decline in the future due to climate change. The latter claims are false and based on controversial computer modeling results and unwarranted assumptions about how crops respond to moderate increases in temperature, not on experience or data that OWID should adhere to.

Ritchie's series of articles: “Crop yields have increased dramatically in recent decades, but crops like corn would have improved more without climate change,” “How will climate change affect crop yields in the future?” and “Climate change will affect food production.” “But Here Are the Things We Can Do to Adapt” are broadly well-written, data-driven articles that highlight the current positive impacts of climate change on crop production and the enormous potential of broader penetration of modern agricultural technologies in developing countries describe further increasing production. The only flaws in the articles are that they cite unconfirmed studies based on flawed climate model predictions to speculate about what would have happened to some crops without warmer temperatures and what might happen in the future.

Ritchie's series begins on a solid basis, highlighting the tremendous growth in grain production and regionally important staple foods. Ritchie writes:

When we consider the net impact of climate on food production, we need to consider three key factors: higher CO2 concentrations, warmer temperatures, and changes in precipitation (which can cause too much or too little water).

…

Carbon dioxide supports plant growth in two ways.

First, it increases the rate of photosynthesis. Plants use sunlight to produce sugar from CO2 and water. When there is more CO2 in the atmosphere, this process can happen faster.

…

Second, it means plants can use water more efficiently

Ritchie then explains in detail how higher CO2 concentrations have increased crop yields. This is a fact that Climate Realism has already pointed out in more than 200 articles, here, here and here, to name just a few examples. Data from the UN Food and Agriculture Organization (FAO) shows that wheat, rice, corn and other top cereal crops have continued to set new records for yield and production during the recent period of moderate warming.

• Grain yields have increased nearly 52 percent, with the most recent yield record set in 2022; And
• Grain production grew by around 57 percent. (see table below)

There are three grains that Ritche expresses concern about: corn, millet and sorghum, and claims that these would have increased more without climate change, but that is based on a counterfactual analysis based on computer model projections, not data. She cites studies suggesting that many of the areas where these crops are grown have exceeded or will soon exceed their optimal growing temperatures, with any increase beyond the maximum optimal range resulting in decreasing yields. However, despite increases of 1.3 to 1.5 °C over the past century, all three of these crops have experienced significant yield increases in recent decades, both globally and in tropical developing countries in Asia and Africa, from which they may not be fully benefiting could CO2 fertilization.

Regarding corn, FAO data shows that global corn yields increased by about 55 percent between 1991 and 2022 and by about 49 percent in Africa.

FAO data for millet and sorghum are similar, with each crop showing significant yield increases over the last three decades of moderate warming worldwide and across Africa and Asia. (see graphic below).

As has been discussed in more than 200 articles on climate realism, what is true for global grain production is also true for most crops, such as fruits, legumes, tubers, and vegetables, in most countries around the world. Yields have repeatedly reached record levels during the recent period of climate change, food security has increased and hunger and malnutrition have declined.

Ritchie cites some studies that suggest corn, millet and sorghum yields would have been even higher without warming, resulting in many of their growing areas experiencing temperatures outside their optimal range – a problem that will arise in the future will only increase if CO2 emissions are not limited – however, such claims have a number of flaws. First, most of the regions relevant to the growth of corn, millet, and sorghum lie across or near the equator. However, climate change theory suggests that equatorial regions are least likely to see a sharp increase in temperature – rather, temperatures near the poles are expected to rise dramatically. A small or no increase in temperature in the affected regions means that exceeding what some scientists suspect are optimal temperatures should not be a problem.

Second, Ritchie is right that changes in rainfall can reduce crop production, but again, that shouldn't be a cause for concern. Many of the areas in Africa and Asia highlighted by Ritchie experience periodic or even seasonal droughts. Since, as Ritchie notes, CO2 fertilization causes crops to use water more efficiently and lose less water through transpiration, crops should benefit. On the other hand, many countries in Africa and Asia rely on rainfall for crop production and have limited access to modern irrigation infrastructure. This is where climate change helps because most research suggests, and the IPCC also predicts, that climate change will lead to more rainfall, which means more water for crops, and if the water is seasonal, as is the case in many countries is, more water can be stored for use when it is not raining or snowing.

Third, the claim that climate change is damaging crops is theoretically contradictory. Climate alarmists claim that higher CO2 emissions lead to rising temperatures – if so, the higher temperatures are a byproduct of rising CO2 emissions, meaning that temperatures might not rise without CO2 emissions. Nevertheless, CO2 is the key factor for increasing crop yields. Without rising CO2, crop yields would have increased and would continue to grow more slowly, if at all, than before. According to this theory, if you want to reap the benefits of CO2 fertilization, you have to accept the moderate increase in temperature. Reducing CO2 levels to avoid a minimal increase in temperature would mean killing the golden goose for crop yields, resulting in a larger decline or slower yield growth than any modest yield decline that might result from the associated supposedly small increase in temperature.

What is left for us? Crop yields have increased due to rising CO2 concentrations, reducing hunger. Furthermore, unless climate policy leads to lower CO2 concentrations, there is no reason to believe that CO2 fertilization will not result in higher yields in the foreseeable future.

On the other hand, Ritchie points out that any foreseeable negative impacts of climate change on crops, particularly in developing countries, would be far outweighed by wider access to modern agricultural technologies such as fertilizers, pesticides, modern agricultural equipment, etc. infrastructure. As Ritchie writes:

[T]Here are other things we can do to mitigate this risk and counteract some of these pressures.

Even today, there are still large gaps in returns around the world. “Yield gaps” are the difference between the yields farmers currently earn and those they could achieve if they had access to the best seeds, fertilizers, pesticides, irrigation and practices that already exist today.

Let’s take Kenya and corn as an example. Farmers currently grow around 1.4 tonnes per hectare. However, researchers estimate that farmers could achieve 4.2 tonnes if they had access to the best technologies and practices available today. This means the yield gap is 2.8 tonnes. …

In some of the worst climate scenarios, Kenya could see a 20 to 25 percent decline in corn yields. If nothing else changes, this would reduce the current yield of 1.4 tonnes to around 1.1 tonnes, a decrease of 0.3 tonnes.

However, the current yield gap of 2.8 tonnes is much larger than the 0.3 tonnes decline that would be expected due to climate change.

Yet modern agriculture relies heavily on the use of fossil fuels: the chemicals used to promote plant growth; the chemicals used protect plants from pests; to the machines used for planting, watering, harvesting, storing and transporting crops. So for agriculture, possible negative impacts of climate change on agriculture from the use of fossil fuels are far outweighed by the enormous benefits that their use brings directly to food producers and consumers.

Without CO2 and modern, fossil-intensive agricultural infrastructure, high yields are not possible. That's the general lesson readers should take away from Ritchie's Our World In Data series of articles.

H. Sterling Burnett

H. Sterling Burnett, Ph.D., is director of the Arthur B. Robinson Center on Climate and Environmental Policy and managing editor of Environment & Climate News. In addition to directing the Heartland Institute's Arthur B. Robinson Center on Climate and Environmental Policy, Burnett compiles Environment & Climate News, is editor of Heartland's Climate Change Weekly email, and host of the Environment & Climate News podcast.

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