The University of Southampton

Tag: Food Security

UK Food in a climate crisis?

Posted on by Phoebe O'Brien

British food security is under threat due to Climate change.

If you haven’t heard of ‘climate change’ you‘ve either been living under a rock for the last 30 years or getting yourself elected as leader the free world. But not much has changed, Winter’s a little warmer, summer’s a little wetter? We’ve heard of extreme weather conditions in some far corners of the globe but unless you’ve been planning a trip there, it’s unlikely to affect our everyday lives. But behind supermarkets sliding doors lurks a real peril, one directly impacting Britons at their most vulnerable part, our Achilles heel, our pockets. As crop production is jeopardised, already inflated prices are set to rise, correlating with the environmental changes induced by human pollution (Lobell, 2007).

Figure 1. A familiar slight, well stocked fruit and veg for public consumption. But for how long? (WordShore (flickr), 2016)
Figure 1. A familiar slight, well stocked fruit and veg for public consumption. But for how long? (WordShore (flickr), 2016)

Food security is perhaps the most important commodity provided by the planet. At a glance the effects of climate change, seem on the whole, to be exactly what farmers are looking for in terms of improving yield from their crops. It’s wet, hot, there’s more CO2, more decomposition and available nutrients, just what plants need right? But this is not always the case, although higher CO2 levels does stimulate plant growth, it is counteracted by the increase in temperature and ozone, a molecule with harmful effects on plant tissue(Hogsett, et al 1997). Warming decreases the quality of the crops produced, grains are less dense and seeds contain less oil, as well as favouring growth and proliferation of weeds into new areas, due to the differences in how they photosynthesise (Fuhrer, 2003. Martre, 2017).

Figure 2. The graph from DEFRA (Department for Environmental Food and Rural Affairs) shows billions of pounds worth of imported food, especially fruit and vegetables. (Source: DEFRA Food Statistics Pocketbook 2016)
Figure 2. This graph from DEFRA (Department for Environmental Food and Rural Affairs) shows billions of pounds worth of imported food, especially fruit and vegetables. (Source: DEFRA Food Statistics Pocketbook 2016)

It is no secret that as a nation we currently import almost half of our food and animal feed from overseas (Ruiter et al 2015). In response to huge population increases of 3 Million on average every decade since the baby boomers of the 50s(Humby, 2016) and market for year-round exotic produce. But tropical regions are likely to suffer much more, even a slight temperature increase interfering with developmental and growth processes beyond already stretched thresholds, meaning production in these areas will fall hugely(Challinor, 2008). Excess precipitation, effectively drowning roots and drought adding another uncertain dimension to the mix(Amedie, 2013).

“[In staples like wheat, maize and barley] warming has resulted in annual combined losses of $5 billion per year, as of 2002” -Lobell, 2007

Environmental change is going to effect everyone in one way or another, we rely on plants for food, clothing, oxygen, medicine and much more. Prices of everyday commodities reflect the quantity and quality of production processes. The result is innumerable aspects of our lives being changed, in some way by the unsustainable practices we are complicit to on a daily basis(Lepetz et al., 2009).

Research into genetic modification of crop plants provides some relief in the challenges ahead, improving crop plant coping mechanisms and yield potential (Martre et al 2017), as well as a decrease in the consumption of animal products due to their high carbon footprint and inefficiency(Ruiter et al 2015). For now it will be a 4p increase in a farmhouse loaf and 10p extra for sunflower oil, but immediate action is necessary to prevent a large-scale food shortage in the near future.

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References:

Amedie, F.A., (2013). Impacts of Climate Change on Plant Growth, Ecosystem Services, Biodiversity, and Potential Adaptation Measure. , pp.1–61.

Challinor, A.J. & Wheeler, T.R., (2008). Crop yield reduction in the tropics under climate change: Processes and uncertainties. Agricultural and Forest Meteorology, 148(3), pp.343–356.

Fuhrer, J., (2003). Agroecosystem responses to combinations of elevated CO2, ozone, and global climate change. Agriculture, Ecosystems and Environment, 97(1–3), pp.1–20.

Hogsett, W.E., J.E. Weber, D. Tingey, A. Herstrom, E.H. Lee and J.A. Laurence. (1997). An approach for characterizing tropospheric ozone risk to forests. Environmental Management 21:105-120.

Humby, P. (2016). Overview of the UK population: February 2016. [ONLINE] Available at: https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/articles/overviewoftheukpopulation/february2016. [Accessed 13 March 2017].

Lepetz V., Massot, M. & Schmeller, D.S., & Clobert, J., (2009). Biodiversity monitoring: some proposals to adequately study species’ responses to climate change. Biodiversity and Conservation 18, 3185- 3203

Lobell, D.B. & Field, C.B., (2007). Global scale climate–crop yield relationships and the impacts of recent warming. Environmental Research Letters, 2(1), p.14002.

Martre, P., Yin, X. & Ewert, F., (2017). Modeling crops from genotype to phenotype in a changing climate. Field Crops Research, 202, pp.1–4. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0378429017300242.

Ruiter, H. de et al., (2015). Global cropland and greenhouse gas impacts of UK food supply are increasingly located overseas. Journal of The Royal Society Interface, 13(114). Available at: http://rsif.royalsocietypublishing.org/content/13/114/20151001.abstract.

WordShore (flickr), (2016), Fruit (WordShore)[ONLINE]. Available at: https://hiveminer.com/Tags/hebrides,solas [Accessed 15 March 2017].



Climate Change IS happening, and it’s set to starve the planet… (The opposite of FAKE NEWS!)

Posted on by Anonymous

With the large scale funding cuts of the Environmental Protection Agency in the USA, the current rapid rates of climate change and CO2 release show no hope of stopping.

But seeing as though plants breathe using CO2 (through the process of photosynthesis), and use carbon in their growth, surely the increased amounts of CO2 being pumped into our atmosphere is a good thing for plants?  As studies have shown; perhaps not…

Plants require very specific environmental conditions to function efficiently, and any changes in these conditions can be detrimental.  Although it has been shown that increased CO2 initially causes an increase in the rate of photosynthesis and growth of leaves and roots (Taylor et al 1994), generally, in the long-term, the stimulation of photosynthesis is actually suppressed!

This is mainly due to negative effects on the plants function, such as the build-up of excess starch (sugars) in leaves via increased photosynthesis, hindering breathing of CO2 via pores; called the stomata (Makino & Mae 1999), and increased CO2 also causes the stomata to partially close (Singh 2009), resulting in an inability to respire efficiently (Ryan 1991).

The mechanism for respiration in a plant leaf, through the stomata.
The mechanism for gas exchange in a plant leaf, through the stomata.  Source: Understanding Evolution

The failure to respire efficiently can cause the death of many food crops globally that are vital to feeding our populations!

Increased environmental CO2 also results in global warming due to increased reflection of the Sun’s radiation back to the Earth’s surface; and a temperature increase of 2-3⁰C over the next 30-50 years (IPCC 2007) is predicted to cause problems for our crops.  For example, warmer temperatures affect plants mainly when they are developing, and this has been shown to reduce the numbers of our food crop plants by 80%-90% (Hatfield & Prueger 2015), having dire consequences for our food supplies!

The global change in surface temperature from 1901-2012. A worrying trend that is set to worsen... Source: National Snow & Ice Data Center
The global change in surface temperature from 1901-2012. A worrying trend that is set to worsen… Source: National Snow & Ice Data Center

Climate change is also set to increase the frequency of extreme weather events (Rosenzweig et al 2001). With increased storms and flooding drowning plants in some areas, and in other areas increased drought, resulting in a lack of water for plants to function with, which they rely heavily on for processes such as photosynthesis, vital for growth and survival.  The equation for photosynthesis is shown below, in case you have forgotten…

 

The equation for photosynthesis, showing how carbon dioxide and water are transformed into oxygen and sugars through the light energy from the sun hitting the chlorophyll pigments in the plants cells.
The equation for photosynthesis, showing how carbon dioxide and water are transformed into oxygen and sugars through the light energy from the sun interacting with the chlorophyll pigments in the plants cells.

 

With increasing global temperatures, drought affected areas will increase from 15.4% to 44.0% by 2100 (Li et al 2009) – resulting in less land to grow crops, which will be disastrous for our food security, along with the fact that the number of suitable growing days per year for our crops will decrease by 11% by the year 2100 (Mora et al 2015)!

A sunny day on a Californian beach? Not exactly… This is Californian farmland suffering from a severe drought – completely unusable!
A sunny day on a Californian beach? Not exactly… This is Californian farmland suffering from a severe drought – completely unusable! Source:  New York Times

 

With the saying “Feed the World” becoming more and more poignant, our future looks bleak, as we are set to have less food security per person than ever before due to the detrimental effects that climate change will have on plant function. Also, plants not only provide food, but are also at the heart of our medicines and resources! So maybe Donald Trump ought to reconsider his views on climate change before threatening his new healthcare system before it has begun.

Word Count: 500

 

References:

Hatfield, J. and Prueger, J. (2015). Temperature extremes: Effect on plant growth and development. Weather and Climate Extremes, 10, pp.4-10.

IPCC, (2007). Climate Change 2007: Impacts, Adaptation and Vulnerability. New York: Cambridge University Press, p.17.

Li, Y., Ye, W., Wang, M. and Yan, X. (2009). Climate change and drought: a risk assessment of crop-yield impacts. Climate Research, 39, pp.31-46.

Makino, A. and Mae, T. (1999). Photosynthesis and Plant Growth at Elevated Levels of CO2. Plant and Cell Physiology, 40(10), pp.999-1006.

Mora, C., Caldwell, I., Caldwell, J., Fisher, M., Genco, B. and Running, S. (2015). Suitable Days for Plant Growth Disappear under Projected Climate Change: Potential Human and Biotic Vulnerability. PLOS Biology, 13(6), p.e1002167.

Rosenzweig, C., Iglesius, A., Yang, X., Epstein, P. and Chivian, E. (2001). Climate change and extreme weather events – Implications for food production, plant diseases, and pests. Global Change & Human Health, 2(2), pp.90-104.

Ryan, M. (1991). Effects of Climate Change on Plant Respiration. Ecological Applications, 1(2), pp.157-167.

Singh, S. (2009). Climate change and crops. 1st ed. Berlin: Springer, pp.5-6.

Taylor, G., Ranasinghe, S., Bosac, C., Gardner, S.D.L. and Ferris, R. (1994). Elevated CO2 and plant growth: cellular mechanisms and responses of whole plants. Journal of Experimental Botany, 45, pp.1761-1774.



Nasty Neonicotinoids: The cause of declines in Birds, Bees and Butterflies

Posted on by Imogen Ryan

 

As agriculture has intensified over the last century we have seen falling food prices and bigger fruit and veg, but what is the cost to our wildlife?

The increase in size of modern arable fields provides a veritable feast for many pests, destroying large areas of crop and literally eating into farmer’s profits. This has led to a rise in the use of pesticides to control these pests. However, not all the animals that are negatively affected by pesticides are harmful to crops, in fact some are beneficial.

Neonicotinoids

In the 1990’s a group of insecticides called neonicotinoids were developed which could be added to seeds before planting rather than externally sprayed onto the plants. The plant incorporates the chemical into all its tissues, giving insect pests a fatal dose upon taking a bite (Gilburn, 2015). This is good news for those beneficial animals that don’t munch their way through the crop right?

Wrong! The chemical gets into every part of the plant including the pollen and nectar (Blacquire et al 2012) which bees and butterflies feed on while pollinating plants. Farmland birds also often eat the seeds before they sprout. These animals don’t even have to be in the field to be affected as the majority of the chemical is not taken up by the plant and is leached into the soil water (Hallman et al 2014) and transported to wildflower field margins and neighbouring land.

What are the effects? 

Butterflies

The populations of widespread butterflies on monitored UK farmland sites have declined by 58% between 2000 and 2009 (Brereton et al 2011). This is negatively correlated with the increase in the use of neonicotinoids (Gilburn, 2015). Although it has not been proved to be a cause and effect relationship, the sudden decline in butterflies has not been seen in Scotland (Brereton et al 2011) where less neonicotinoids are used (Defra, 2014).

Painted Lady Butterfly -Alamy

Bees

Neonicotinoids are also threatening bees, impairing their homing ability and learning as well as their immunity to viruses. The chemical also reduces the growth of the colony and the production of queens (Cresswell, 2011). A recent field study by Rundolf et al (2015) has shown that the density of wild bees, nesting of solitary bees and growth of bumblebee colonies have all been reduced by neonicotinoid treated rape seeds.

neonicotinoid-pesticides-their-effect-on-bee-colonies-the-facts

Out for the count. Julia Garvin

 

Birds

A decline in insectivorous farmland birds, correlated with neonicotinoid use, has also been seen in the Netherlands (Hallman et al 2014). This is thought to be due to directly consuming the poisonous seeds (Goulson, 2013) or through the reduction in their insect food source.

Grey Partridge-Cambridge Bird Club

 

Do we need neonicotinoids anyway?

The use of neonicotinoids also appears to have no benefits to agricultural yields of soybean (Myers, 2014), Sunflower and Maize crops (Susuki, 2014). Methods like Integrated Pest Management can reduce the number of pests without the powerful chemicals so isn’t it time we put nature before ease?

More information on the effect on bees

References  painted-lady 

Blacquiere T, Smagghe G, Van Gestel CAM, Mommaerts V. 2012. ` Neonicotinoids in bees: a review on concentrations, side-effects and risk assessment. Ecotoxicology 21:973–992

Brereton TM, Roy DB, Middlebrook I, Botham M, Warren M. 2011. The development of butterfly indicators in the United Kingdom and assessments in 2010. Journal of Insect Conservation 15:139–151

Cresswell JE. 2011. A meta-analysis of experiments testing the effects of a neonicotinoid insecticide (imidacloprid) on honey bees. Ecotoxicology 20:149–157

Defra. 2014. Pesticide usage statistics. Available at https://secure.fera.defra.gov.uk/pusstats/ (accessed March 2017).

Gilburn, A.S., Bunnefeld, N., Wilson, J.M., Botham, M.S., Brereton, T.M., Fox, R., and Goulson, D. (2015). Are neonicotinoid insecticides driving declines of widespread butterflies? PeerJ:e1402

Goulson, D. (2013). An overview of the environmental risk posed by neonicotinoid insecticides. J. Appl. Ecol. 50, 977-987

Hallmann CA, Foppen RPB, Van Turnhout CAM, De Kroon H, Jongejans E. 2014. Declines in insectivorous birds are associated with high neonicotinoid concentrations. Nature 511:341–343

Myers, C., Hill, E. (2014). Benefits of Neonicotinoid Seed Treatments to Soybean Production. US Environmental protection agency

Rundlof M, Andersson GKS, Bommarco R, Fries I, Hederstrom V, Jonsson O, Klatt BK, ¨ Pedersen TR, Yourstone J, Smith HG. 2015. Seed coating with a neonicotinoid insecticide negatively affects wild bees. Nature 521:77–80

Susuki, D. (2014). More Bad News for Bees. Available at http://www.ecology.com/2014/10/31/the-new-word-for-bees/ (accessed March 2017)

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How do you like your toast in the morning? Without the worry of food security?

Posted on by Imogen Vieten

80% of human calorie intake comes from 6 major crops including – maize, wheat and rice1. For all people, at all times to have physical and economic access to sufficient food needed for a balanced diet2–food security, the production and distribution of these crops is vital.

Present day representation of global vulnerability to food insecurity8. Explore scenarios of Greenhouse gas emissions and adaptation to climate change impacts on food security by clicking on the link: http://www.metoffice.gov.uk/food-insecurity-index/ Present day representation of global vulnerability to food insecurity3. Explore scenarios of Greenhouse gas emissions and adaptation to climate change impacts on food security by clicking on the image.

A growing human population increases pressure to enhance crop production. 1 billion ha of land will be converted by 2050 for agriculture, reducing absorption of atmospheric carbon dioxide by plants2 and restoration of gaseous balance in the atmosphere, with fewer plants to act as a CO2 ‘sink’.

Human induced climate change is negatively affecting ecosystems, crop yield and production. Since the industrial revolution greenhouse gas emissions have risen, with atmospheric CO2 levels currently at 406.42ppm4, meaning plants are growing in conditions not experienced for 26 million years5.

Impacts of future climate change are predicted to be severe, varying between regions, through changes in temperature, precipitation and increases in extreme weather events. Methods of crop production such as sustainable intensification are needed to increase yields and overcome threats to livelihoods and food security2.

Will increased CO2 result in higher crop yields?

During photosynthesis plants use CO2, water and light to produce oxygen and carbohydrates for growth. Efficiency of this depends on the enzyme Rubisco, which functions better in high CO2, shown experimentally to increase photosynthesis by 58%5. There is evidence that the number and size of individual cells increase in elevated CO26, showing species specific adaptive ability7,  indicating potential to increase crop yield. However other climatic stresses will have negative effects.

The temperature dependant action of Rubisco may become less efficient with rising global temperatures. Furthermore in the long term, plants can acclimatise as additional carbohydrates produced from photosynthesis cannot be used5.

During extended periods of high CO2 exposure the number of stomata- pores used in gaseous exchange in leaves, may decrease indicating that photosynthetic rate will too7.

How will crop production be affected?

For sustainable intensification sufficient water and nutrients8 are required, which will be threatened by increased extreme weather events- from drought affecting water supply to storms where heavy downpours can wash away top soil, reducing land fertility.

Threats to global productivity and changes in yield could have impacts worldwide8. If production decreases, prices of grain products and meat reliant on grain as a feedstock will increase8. Furthermore lower agricultural output, especially in the developing world, leads to lower incomes, with the poorest suffering the most.

High CO2 can decrease food quality with a decline in protein, nitrogen, zinc and iron concentrations in crops9, potentially causing adverse health effects, and necessitating consumption of greater quantities.

Securing the future

FACE (Free-air concentration enrichment) experiments expose crops to elevated CO2 to examine responses and adaptions of ecosystems. Research to develop climate resilient crop varieties to better cope with heat, drought and salinity is also being conducted.

By adapting farming mechanisms and increasing yield and tolerance of essential crop species to environmental extremes, can we ensure food security? Yes, the time to act is now!

 

Discover more about how farmers may adapt their practices to a changing climate in the video ‘Feeding Nine Billion’10

 

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References

  1. Campell, N,A., Reece, J, B., Urry, L,A., Cain, M,L., Wasserman, S, A., Minorsky, P, V., Jackson, R, B. (2015). Seed Plants. In: Wilbur, BBiology A Global Approach. 10th ed. Essex: Pearson. p707.
  2. Sunderland, T., Powell, B., Ickowitz, A., Foli, S., Pinedo-Vasquez, M., Nasi, R. and Padoch, C. (2013). Food security and nutrition: The role of forests. Center for International Forestry Research. Discussion Paper, p1-20.
  3. Met Office. (2017).Food Insecurity Climate Change. Available: http://www.metoffice.gov.uk/food-insecurity-index/. Last accessed 18th March 2017.
  4. CO2 (2017). Earth’s CO2 home page. Available: https://www.CO2.earth/earths-CO2-main-page. Last accessed 20th March 2017.
  5. Drake, B, G. and Gonzàlez-Meler, M, A. (1997). More Efficient Plants: A Consequence of Rising Atmospheric CO2?.Annual Review of Plant Physiology and Plant Molecular Biology. 48, p609-639.
  6. Taylor, G., Ranasinghe, S., Bosac, C., Gardner, S and Ferris, R. (1994). Elevated CO2 and plant growth: cellular mechanisms and responses of whole plants. Journal of Experimental Botany. 45 (Special Issue). P 1761-1774
  7. Long, S, P., Ainsworth, E, A., Rogers, A. and Ort, D, R. (2004). Rising Atmospheric Carbon Dioxide: Plants FACE the Future.Annual Review of Plant Biology. 55, p591-628.
  8. Nelson, G, C., Rosegrant, M, W., Koo, J., Robertson, R., Sulser, T., Zhu, T., Ringler, C., Msangi, S., Palazzo, A., Batka, M., Magalhaes, M., Valmonte-Santos, R., Ewing, M. and Lee, D. (2009). Climate Change: Impact on Agriculture and Costs of Adaptation.International Food Policy Research Institute. Available at: http://www.fao.org/fileadmin/user_upload/rome2007/docs/Impact_on_Agriculture_and_Costs_of_Adaptation.pdf. Last accessed 19th March 2017
  9. Myers, S., Zanobetti, A., Kloog, I., Huybers, P., Leakry, A., Bloom, A., Carlisle, E., Dietterich, L., Fitzgerald, G., Hasegawa, T., Holbrook, N., Nelson, R., Ottman, M., Raboy, V., Sakai, H., Sartor, K., Schwartz, J., Seneweera, S., Tausz, M. and Usui, Y. (2014). Increasing CO2 threatens human nutrition. Nature, 510, p139-142
  10. Fraser, E. (2014). Feeding Nine Billion Video 6: Climate Change and Food Security. Available: https://www.youtube.com/watch?v=cYq2elstFWQ. Last accessed 18th March 2017.


Are plants on their way to killing us?

Posted on by Charlotte Alanine

          Have you ever noticed how much easier it is to breathe on a jog through a luscious park or a woodland compared to the inner city? This is because the air we breathe comes from the photosynthetic process plants provide. In this reaction, plants extract energy from carbon dioxide (CO2) combined with sunlight as well as other organic soil materials and release Oxygen (O2) as a by-product which we then benefit from.

 

         Photosynthesis under increasing CO2

          Each year since 1959, approximately half of the CO2 emissions we produce linger in our atmosphere (Le Quéré, et al., 2009). With atmospheric levels of CO2 on the rise as a result of our activities, the logical outcome would be that plants have additional CO2 to photosynthesise, allowing for more oxygen for us, right? Indeed, short-term increases have no negative impacts on photosynthesis. In fact, a study suggested they became more efficient at recycling CO2 (Besford, et al., 1990) as demonstrated in the positive feedback photosynthesis and growth of P.cathayana (Zhao, et al., 2012). However, under long-term carbon dioxide exposure, plants lost all photosynthetic gain (Besford, et al., 1990). Other studies have investigated the effects of increasing CO2 levels on plants and it has recently been found that previous models may have overestimated  the ability of plant “sinks” to make use of the additional human-related carbon. A “sink” is a location where carbon dioxide accumulates and is absorbed by plants much like running water down a sink.

 

From carbon sinks to carbon sources

        In 1991, Arp projected that plants in the field would not experience a decrease in photosynthetic abilities as a result of atmospheric CO2 increase. However, more recently in 2015, Wieder et al. reported that photosynthetic processes were limited by nutrient availability, in which phosphorus and nitrogen (Aranjuelo, et al., 2013) were the main limiting factors.

Figure 1. Modelling of changes in mean terrestrial carbon storage from an initial record 1860-1869 (top) to the 2100 projection with limited nitrogen and phosphorus (bottom). Source: Wieder et al. (2015)
Figure 1. Modelling of changes in mean terrestrial carbon storage from an initial record 1860-1869 (top) to the 2100 projection with limited nitrogen and phosphorus (bottom). Source: Wieder et al. (2015)

          In addition, their models projected that by 2100, plants which were once considered sinks may actually be turning into carbon sources (fig.1). This means they could be emitting more carbon than they absorb as a result of increasing carbon dioxide in the air in combination with the insufficient amounts of other organic materials (nitrogen, phosphorus, minerals, etc.) necessary for photosynthesis and consequently accelerating the rate of climate change which is bad news for us. Plants will essentially be slowly suffocating us as we rely on them for clean air.

 

 

 

A threat to food security

          Likewise, as a result of intensifying agriculture, soils are becoming increasingly eroded. For one, this means they are unable to store and process atmospheric carbon as efficiently and there is a lack of nutrients made available to plants (Lal, et al., 2008). This, coupled with the higher concentrations of CO2, poses a great threat to major crop plants such as oilseed rape (Franzaring, et al., 2011) and wheat (Uddling, et al., 2008). In laboratory studies, these crop plants tended to reduce the quality and quantity of their seeds in high concentrations of CO2.

          Emissions are not only posing a threat to a plant’s capacity to recycle air but also put our food security at risk.

References

Aranjuelo, I., Cabrerizo, P., Arrese-Igor, C. & Aparicio-Tejo, P., 2013. Pea plant responsiveness under elevated [CO2] is conditioned by the N source (N2 fixation versus NO3 – fertilization). Environmental and Experimental Botany, Volume 95, pp. 34-40.

Arp, W., 1991. Effects of source-sink relations on photosynthetic acclimation to elevated CO2. Plant, Cell and Environment, Volume 14, pp. 869-875.

Besford, R., Ludwig, L. & Withers, A., 1990. The Greenhouse Effect: Acclimation of Tomato Plants Growing in High CO2, Photosynthesis and Ribulose-1, 5-Bisphosphate Carboxylase Protein. Journal of Experimental Botany, 41(8), pp. 925-931.

Franzaring, J., Weller, S., Schmid, I. & Fangmeier, A., 2011. Growth, senescence and water use efficiency of spring oilseed rape (Brassica napus L. cv.Mozart) grown in a factorial combination of nitrogen supply and elevated CO2. Environmental and Experimental Botany, Volume 72, pp. 284-296.

Lal, R. et al., 2008. Soil erosion: a carbon sink or source?. Science, 319(5866), pp. 1040-1042.

Le Quéré, C. et al., 2009. Trends in the sources and sinks of carbon dioxide. Nature geoscience, 2(12), pp. 831-836.

Uddling, J. et al., 2008. Source-sink balance of wheat determines responsiveness of grain production to increased [CO2] and water supply. Agriculture, Ecosystems and Environment, Volume 127, pp. 215-222.

Wieder, W., Cleveland, C., Smith, W. & Todd-Brown, K., 2015. Future productivity and carbon storage limited by terrestrial nutrient availability. Nature, 8(6), pp. 441-445.

Zhao, H. et al., 2012. Sex-related and stage-dependent source-to-sink transition in Populus cathayana grown at elevated CO2 and elevated temperature. Tree Physiology, Volume 32, pp. 1325-1338.

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Believe it or not… CLIMATE CHANGE WILL TRUMP U.S.!

Posted on by Hannah Lesbirel

By Hannah Lesbirel student at University of Southampton

You’ve all seen images of famine and the effect of crop failure on families across the globe. Have you ever pictured that being you? No, me neither.

Surely that can’t happen in the USA- “The greatest country in the World”- people say?

Queues for food rations. This is happening somewhere in the world right now! Imagine, this could be you if nothing is done to reduce the impacts of climate change. Source: http://answersafrica.com/starvation-and-famine-in-africa.htm
Queues for food rations. This is happening somewhere in the world right now! Imagine, this could be you if nothing is done to reduce the impacts of climate change. Source: AnswerAfrica

Some experts argue the increase in CO2 levels, associated with climate change, may in fact contribute to gains in some crops, in some regions of the world. Surely more CO2 means more photosynthesis, right?

However, the negative impacts associated with climate change are expected to reverse the potential benefits (Nelson et al., 2009). Climate change indisputably impacts: global temperatures, frequency and intensity of extreme weather events, CO2 levels and water availability, and without availability of sufficient water and nutrients photosynthesis can’t thrive (Nelson et al., 2009; Hatfield et al., 2011).

The video below summarises the limiting factors of photosynthesis and how they could be influenced by the changing environment.

Temperature Variability

The rate of plant development is primarily influenced by temperature, impacting (Hatfield and Prueger, 2015);

  • Pollen viability
  • Fertilisation
  • Water requirements
  • Grain and fruit formation
  • Length of life cycle

All plants have an optimum temperature in which photosynthesis takes place, too high and enzymes are denatured and too low the catalytic efficiency of these enzymes are reduced. Additionally, higher temperatures are known to encourage weeds, pests and disease.  The figure below shows the predicted temperature due to climate change globally by 2050 (Nelson et al., 2009). If this rise in temperature is to continue, this will reduce crop yields across the globe.

Source: Nelson et al., 2009
Predicted increase in global temperatures by 2050. Source: Nelson et al., 2009
picture1
Once luscious fields becoming barren due to decreased yields as a results of climate change. Source: Crated and Nature 

With warmer temperatures predicted along with the increased probability of extreme temperature events, plant productivity is at serious RISK! Estimations show a significant decline in yields, of between 80-90%, compared to ‘normal’ conditions (Hatfield and Prueger, 2015).

Changes in Precipitation

The concern of rising global temperatures, will be proliferated by changes in precipitation. Increasing the likelihood of crop failure and long term production decline (Nelson et al., 2009).

Despite uncertainty in precipitation change, under future climate change scenarios, the impact of excess and deficit amounts of soil water will be negative for crop production, either drowning or starving the crops of water (Hatfield et al., 2011).

It’s been said that “stronger interannual variability with more extreme year-to-year climate variations…[means] farmers are unable to tune their cropping systems to optimize resources (Bannayan et al., 2010).”

Not only will this have a major impact on human health and well-being. Agriculture contributes over $300 billion to the U.S. economy each year; think of the impact this may have on your health and livelihood.

Decline of Global Markets

On a more global scale, the potential decline in production will reach international levels, as U.S. farms supply 25% of all grain (soybean, wheat and maize) on the global markets (Nelson et al., 2009; USEPA, 2016).

screen-shot-2017-03-06-at-13-24-35
The cycle that could follow the decline in grain production (Nelson et al., 2009).

The ‘domino’ effect of a decline in grain productivity is incomprehensible. The cycle that could follow is shows to the right.

Could we be building a wall between us and future generations? Progress is needed to prevent this shocking reality.

Read more information about the impact of Climate Change on global agriculture from the FAO report on Climate change: Impact on Agriculture and Costs of Adaptation.

 

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Read More:

http://ecoethics.net/cyprus-institute.us/PDF/Rosensweig-Food-Supply.pdf

http://bioenv.gu.se/digitalAssets/1432/1432197_fantahun.pdf

http://www.pnas.org/content/106/37/15594.full