If You Don't Think A One-Degree Temperature Rise Matters, Read This

If You Don't Think a One-Degree Temperature Rise Matters, Read This

It's just one-degree, right? So, how big a difference can it really make? There's a place in the world where we can already look at for an answer. A new study in Nature Climate Change looks at Brazil's Mato Grosso state, a rising agricultural powerhouse in the country and in the world. (Ten per cent of all the world's soybeans already come from there.) It's also an area that has already seen temperatures quickly rise — and will probably keep right on seeing it, by up to an extra two degrees by 2050. Researchers at Brown and Tufts took a look backwards at data since 2002 from the state to see what had already happened with climbing temperatures. What they found was that a single degree of temperature change came along with drops of 9-13 per cent in crop yields of both soybeans and corn.

But these yield drops sound higher than other climate change studies in the past. Why? Because it's not just about what that change in temperatures does to soil and plants — it's also about what that change in temperature does to our behaviour. When conditions change, farms don't just continue on their way, just as they always have. Farms are constantly changing, and farmers try to adapt to their current conditions in what they plant, how much they plant, and how often they plant. If things are bad enough, they may decide that it's simply not likely enough to be profitable to plant certain things at all.

That's exactly what the data showed, when the researchers went into NASA satellite data for a closer look. Almost all of the drop in crop production (70 per cent) wasn't due to smaller yields, it was due to crops not planted at all.

If You Don't Think a One-Degree Temperature Rise Matters, Read This

Brown University / NASA

Of course, this is one case study in one very specific area — different areas will react to the rise in temperature differently and the researchers have already started talking about attempting a similar study inside the US. But there's a larger lesson about climate that can already be stretched outwards.

People sometimes scoff at the meaning of a one-degree temperature rise, saying that no one will really feel the difference between a 30-degree day and a 29-degree day. And that's true in the moment — they do, from a weather-standpoint feel about the same. But it's not about weather, it's about what that rise in temperature does to the world around us, and — especially on farms where a single degree is enough to change how things grow — it's enough to radically change how we live.

Image: Getty

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    Higher temperatures generally means higher crop yields.

      Did you even read the article? Here ill highlight the point you clearly missed

      "What they found was that a single degree of temperature change came along with drops of 9-13 per cent in crop yields of both soybeans and corn."

        djbear, did you spot this bit ' it was due to crops not planted at all' ?
        see the link below where subsistence farmers are abandoning farms because increased productivity from aerial fertilization in more efficiently farmed areas makes small farms no longer economically viable. It's actually good news for forest ecosystems being spun to look bad.

          Did you spot the bit that it was economically not viable as farm practices also change with climate?

    And in the top picture, the farmer is setting fire to the dead leaves which will add to the problem. Brilliant. Says it all for mankind. We're all going to die.

    This is a radical political spin on the story http://www.nytimes.com/2009/01/30/science/earth/30forest.html?_r=2 that farmland is being abandoned due to increased yields caused by increased CO2.
    Turning a good news story where plant growth rates, soil moisture levels and yields have increased into something dire. http://www.nature.com/articles/srep20716
    the upside is that these inductive researchers in abandoning the discipline and philosophy of science are losing credibility as they paint themselves into a corner crying wolf.

      1. Your first link does not support your argument. It states the fact that farms are being abandoned, asserts that this is because they have become uneconomical on a small scale, and claims that better seeds and fertiliser make large farms more efficient. It says nothing about improved yield, especially not from CO2, just efficiency which can come from reduced costs as well as or even instead of more productive crops, and one interpretation gives the implication that because small holdings can't compete yield is DOWN.

      2. Your source article is seven years old, what has happened since then?

      3. It talks about Panama, not Brazil, which is a completely different location and may have different conditions.

      4. You obviously haven't actually read the study you are disparaging, which clearly identifies exactly what is says, a drop in agricultural output. If you want to make the claim that they are abandoning science, you need to show that they are wrong and output has gone up, anything else is just your wishful thinking. In other words, put up the data or shut up.

        From my knowledge on the subject I would further add that CO2 would only improve leaves and overall growth but would not help fruit production which is based more on soil organics and climate. I would go so far as to suggest that any plant that produces fruit would be negatively affected and any plant that produces leaves may see some improvement in some cases.

          You're right of course - the plants carbohydrate /hydrocarbon yield will increase, sugars will increase, but some studies have shown a reduction in protein concentrations. This is not surprising but to be fair a study which looked at irrigated fruit V non irrigated fruit would find the same thing - more water mass diluting the concentration of other components.

          One evaluation found that for 1kg of CO2 enriched growth rice, one would need to eat 1 single chick pea to make up for the lost protein (or one weevil) but seriously.. who eats rice for the protein?

          Plants however are bioaccumulators or concentrators.. onions draw sulfur, garlic draws selenium, water hyacinth draws cadmium, cobalt and a large selection of heavy metals from the soil - often in experiments the soils are controlled and you'd be hard pressed to see functional bioaccumulation in trials that weren't actually examining this trait.

          Looking at concentrations of proteins or other factors though, concentration is not total yield - if a plant produced 25kg of food with a 10% reduction of protein that is sold to us as A Bad Thing .. comparing it to a plant with a yield of 1kg however.. doesn't look quite as frighteneing, does it?

        the first link I cited was in reference to the comment in the article that farms ..'simply not likely enough to be profitable to plant certain things at all.'

        If the 'old' article is not good enough because it's 'old, here's a 2016 article, saying the same thing but with more pronounced effects. - http://phys.org/news/2016-02-carbon-dioxide-global-dryland-greening.html. If you look you'll find the CSIRO had an article along the same lines up which they've selected to remove - although the internet archive preserved it. But whether it's old should not matter -

        It's nice you ask for evidence to support theories - botanists have known about increased yields from CO2 for a very long time. The current crop of modelers and theorists seem to avoided studying the carbon cycle and many of their postulations fly solidly in the face of known facts. Here's a very old article from 1920 describing practical observations of CO2 enriched yields. http://sealevel.info/ScientificAmerican_1920-11-27_CO2_fertilization.html

        Agricultural output has increased across the world by 14-17%, famland use has fallen substantially (in some areas as much as 90% - though if I wanted to generate a hysterical headline I could say 100% by plotting single farms) .. Much of this farmland has reverted to a wild state. Reason for concern? none I can see.

        I should add regarding the comment ' put up the data or shut up' that handing a paper such as the above to a lecturer pre-1980's even as a student would have resulted in an outright fail. Observations are followed by statements of findings, any speculation was considered utterly irrelevant. This is what occurs with the crossover of medical 'studies' into science.. words such as 'could' and 'may' were contrary to te philosophy of science and irrelevant.

        As to the facts, the onus lies with those of the like who authored this study - as they are seeking to overturn over a century of established science. The carbon cycle is well known to any botanist - increasing CO2 leads to increased plant growth and reduced water consumption. C3 photosynthesizing plants pump water because they are starved of CO2 and they need to photorespire to stay alive in CO2 depleted atmospheres.. increasing CO2 leads to what has been studied, observed and verified - soil moisture levels increase.. additional detritus from plants is used by soil microbes to produce additional nitrogen in this now moist soil, plant growth increases.

        You can look this up anywhere - virtually any plant physiology, agronomy or ecology text is pretty straightforward on how C3, C4 and CAM photosynthesis works.

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