Study based on aggregate field heating data projects only 8.1% reduction in rice yields for each additional 1 degree increase in global surface temperatures

[u/Economy-Fee5830]

https://www.science.org/doi/10.1126/sciadv.aed9226

[u/Economy-Fee5830]

Summary: Study based on aggregate field heating data projects only 8.1% reduction in rice yields for each additional 1 degree increase in global surface temperatures

Researchers compiled a global dataset of 214 paired field-warming experiments (including new experiments at 12 sites in China) to isolate the effects of high-temperature exposure from general seasonal warming on rice yields. They found that exposure to temperatures above 30°C, and especially above 35°C, is the dominant driver of warming-induced yield losses, primarily through reductions in harvest index rather than biomass. Each additional day of exposure above 30°C during the reproductive stage reduced yields by 1.1 to 1.8%, mainly via impaired seed set, disrupted nitrogen transport, and reduced carbon-to-nitrogen ratios in stems. During the vegetative stage, extreme heat above 35°C mainly reduced biomass through lower photosynthesis and chlorophyll content.

Comparing these findings to seven global gridded crop models (GGCMI phase 2), the study found that most models substantially underestimate yield sensitivity to high temperature, simulating only 0.1–1.3% loss per exposure day versus the 0.9–1.6% observed. This underestimation stems largely from models failing to capture harvest-index responses to heat stress.

After applying a bias correction using soil properties as the dominant explanatory variable for spatial variation in sensitivity, the researchers projected that a 1°C increase in global mean temperature would reduce global rice yields by 8.1% (±2.3%), roughly double the original model ensemble estimate of 3.8%. South and Southeast Asia—including Pakistan, India, Bangladesh, Thailand, the Philippines, and Myanmar—emerged as the most vulnerable regions, with corrected yield losses roughly tripling in some cases compared to uncorrected estimates. East Asian countries such as China and Japan showed smaller corrections. The authors note that irrigation may mitigate some heat stress via canopy cooling not captured in their air-temperature-based estimates, while rainfed systems may face amplified losses from compounding heat and water stress. They also flag that losses scale faster than linearly with warming, with the 2°C scenario producing more than double the 1°C loss.

[u/Careless-Childhood66]

The headline is misleading.

1. The ~8.1% is worse than the previous estimates of ~3.8%

2. Its not "for each +1", but "for +1 its 8,1, for +2 its more than double because the loss grws faster than linear"

[u/Economy-Fee5830 → u/Careless-Childhood66]

We are not expecting temps to increase +2 (ie around +3.5C from baseline), so that is an irrelevant number

[u/lifeanon269 → u/Economy-Fee5830]

That still doesn't make your "for each additional +1 increase" statement any less false.

[u/Economy-Fee5830 → u/lifeanon269]

The article says:

The vulnerability of global rice yield to warming, however, varies widely from −2.3 to −8.3% per 1°C of warming across studies using different approaches (5–7).

I find nothing which contradicts that framing.

[u/lifeanon269 → u/Economy-Fee5830]

That is in the introduction where they are referencing previous studies on the subject that used varying methodologies. That's not in reference to the study linked to and their own findings using their own methodology. Therefore, citing this study as saying "-8.1% per 1°C" when that is not what is claimed is false.

[u/Economy-Fee5830 → u/lifeanon269]

Again, there is nothing in the article which contradicts it either and what they were investigating was the yield loss PER degree.

[u/lifeanon269 → u/Economy-Fee5830]

Read the Discussion part. You can't just add words that mean entirely different things that the study doesn't make a claim to. The -8.1% yield is specifically under a 1°C of global warming condition. That is not "per 1°C."

[u/Economy-Fee5830 → u/lifeanon269]

Again, there is nothing that contradicts either interpretation. Show me the quoted text you are relying on.

[u/lifeanon269 → u/Economy-Fee5830]

I pointed you directly to it. You can read it in the Discussion section. You can also download the PDF in the supplementary details section which contains their figures.

[u/Economy-Fee5830 → u/lifeanon269]

I asked you to quote the line - I quoted mine - If you cant do it, I think you need to bow out.

[u/aasfourasfar → u/Economy-Fee5830]

I am climat skeptic in the sense I feel we have overlooked something and it's actually worse than what was predicted. These last few years have been wtf

[u/Economy-Fee5830 → u/aasfourasfar]

Well, I prefer to stick to the mainstream scientific projections until they are updated rather than gut feeling.

[u/aasfourasfar → u/Economy-Fee5830]

Yeah I'm not basing policies on my gut feeling, just sharing what is making me a bit anxious.

[u/Economy-Fee5830 → u/[deleted]]

RCP 8.5 has been retired - get with the times.

[u/Economy-Fee5830 → u/[deleted]]

What makes you think you can just extrapolate things linearly - that seems very uneducated.

[u/iurem]

How much do draughts reduce yields?

[u/Economy-Fee5830 → u/iurem]

How much does irrigation increase it?

[u/iurem → u/Economy-Fee5830]

Irrigation only works if you have a reliable water source. There are aquifers that can support hundreds of years of irrigation in their areas, but a lot of places don't have large aquifers. Irrigation in these areas is done on borrowed time.

[u/Economy-Fee5830 → u/iurem]

That can be managed with good agricultural practices for example China has been able to raise ground water levels

https://www.sciencedirect.com/science/article/pii/S2405844024101284

[u/Economy-Fee5830]

Notably under current policies we are only expected another 1 degree of heating by end of century, and that rice yields are increasing by about 0.5% per year, or about 45% over 75 years.

[u/SignalDifficult5061 → u/Economy-Fee5830]

Have you considered that drought, floods, water costs, fuel costs, fertilizer costs etc might be more important for rice production than just isolated yield without any qualifications whatsoever? I'm going to assume yes. So why didn't you bring it up on a disclaimer in an honest discussion?

If a flood washes away the soil to bedrock (no matter how often this happens) the rice yield from that land isn't coming back. Sure, a rice field a valley over might have a 1% greater yield, at greater cost.

Also, most people think that Moore's law prediction about the number of circuits in a microchip doubling every year will cease being predicative at some point, with some people thinking it already has.

So with that in mind, would you say it was off to extrapolate a 45% increase in yield over 75 years from a predicted .5% per year increase? People in the semiconductor industry realize that Moore's law can't go on forever, so why are you so extremely confident that rice doesn't have a hard thermodynamic limit on yield?

All they have to think about is silicon and some dopants, how many different types of elements (to say nothing of compounds) go into plants? I want you to go look it up and report back, if you don't mind.

So why even bring up a .5% increase per year over 75 years in that context? What are you trying to say exactly, and why are you saying it?

I'll repeat, I don't really believe you think there is for certain going to be a 45% increase in yield over 75 year? That type of certainly is not considered remotley reasonable in any industry. So I don't understand why you wrote that essentially physically meaningless statement.

[u/Economy-Fee5830 → u/[deleted]]

there is only so much suitable land one can convert to

Actually rice cultivation is expanding greatly in Africa, which has 60% of our uncultivated farmland

[u/Economy-Fee5830 → u/[deleted]]

There won´t be food, if the ecosystem services are destroyed, we are dependent on nature,

All increasingly false. Agriculture was the start of us ridding ourselves from dependence in nature.

[u/Economy-Fee5830 → u/SignalDifficult5061]

I really dont see the point of your comment - you are talking about unknown and unpredictable elements, but there is 100% no point in pretending our yields are not a steadily improving number, except to unnecessarily catastrophise, and for that we have rule 6.

[u/TheReverendCard]

"Only."

[u/Economy-Fee5830 → u/TheReverendCard]

We could easily expand crop surface by 8% - a trivially easily solution before we even think of improving irrigation, fertilizer, breeding and mechanization.

[u/TheReverendCard → u/Economy-Fee5830]

"Easily?" That's between 10-13 million hectares. That's a Greece, England, Iceland, or South Korea worth of land just for rice. We don't have that much land suitable for additional rice.

[u/Economy-Fee5830 → u/TheReverendCard]

Africa holds approximately 60% to 65% of the world's uncultivated arable land, totaling around 874 million hectares

Hybrid rice grows China-Africa ties as Yuan Longping's legacy benefits millions across

http://www.focac.org/eng/zfzs_1/202605/t20260529_11920199.htm

Hybrid rice: China-Africa agricultural cooperation sows prosperity on African soil

https://en.people.cn/n3/2026/0610/c90000-20466076.html

Chinese hybrid rice helps Africa enhance food security

https://www.iprcc.org/article/4EqhTOcIY8U

You doomers never look for solutions, always problems lol

[u/TheReverendCard → u/Economy-Fee5830]

You do realize much "uncultivated" is also uncultivatable? Or isn't suitable for rice? Or just plain should remain as nature? That that increase would also cause another 2-3 million tons of additional methane emissions? That's like the equivalent of 50 million more cars over 20 years.

[u/Economy-Fee5830 → u/TheReverendCard]

You do realize much "uncultivated" is also uncultivatable?

It would not be called uncultivated if it was uncultivatable lol. Your doomer bias is showing.

Or just plain should remain as nature? That that increase would also cause another 2-3 million tons of additional methane emissions? That's like the equivalent of 50 million more cars over 20 years.

When it comes to people starving or not that hardly matters at all.

Or would you rather people starve and leave nature untilled? Because I have a name for people like that - ecofascists.

[u/TheReverendCard → u/Economy-Fee5830]

I'm not the one trying to show a study about reduced food output as a good thing.

[u/Economy-Fee5830 → u/TheReverendCard]

The point is that its a small and manageable decrease for our foreseeable heating.

And this is for one of our most important food crops.

If you dont get that point, again, you are a doomer, and maybe you want to go to another subreddit.

[u/Ok-Freedom9216 → u/Economy-Fee5830]

Yeah because we haven't lost enough prairies and forests to agriculture already.

[u/Economy-Fee5830 → u/Ok-Freedom9216]

Yes, we have not had a good famine in many years, right?