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Will Climate Change End Food Security? Or, is the Future Golden with Rice?

Posted on by Jamie Wilkinson

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What is food security?

The World Food Programme defines food security using three major components:

Food Availability – The availability of food on a consistent basis and in sufficient quantities.

Food Access – The ability for people to acquire adequate food quantities through purchase, production or aid.

Food Utilization – The food consumed has a positive nutritional impact on those consuming it.

What Effects will Climate Change have on plants and where?

The effects of climate change will worsen existing stresses, such as poor soils and water (Baulcombe et al 2009). In particular climate change will impact crop yield as well as farm and regional production. This fall in crop production will negatively affect food security.Elevations in atmospheric CO2 will increase the crop yield for many plants such as rice, wheat and soybean (Ainsworth & Long. 2005). However, most other climatic stresses such as increased temperature, lack of nitrogen and reduced precipitation have negative effects on yield.

Image result for food insecurity hotspots
World map highlighting countries at higher risk to losing food security – Maplecroft

The effect of climate change on food security will be varied by region. The areas worst affected are low latitude countries that are still developing (Rosenzweig et al 2014). As in these tropical regions the temperature is already close to the high threshold for production of these cereal grains. Therefore, a small increase in temperature (1-2 °C) will lead to a reduction in crop yield for the major cereals (Peng et al 2004).

Adapting for the Future – It’s not all doom and gloom!

Image result for golden rice

By selecting crops that are more durable to variable climatic conditions and have higher resistance to abiotic stresses, we can maintain food availability and access. Additionally genetically modifying crops so they can cope with inconsistent growing conditions will improve food utilisation. Golden Rice is a way of tackling this problem. It is high in Beta-carotene, a molecule which can be converted by the human body into vitamin A. Vitamin A deficiency (VAD) is a big problem throughout many countries in the world, where crops high in vitamin A can’t grow. In Nigeria 29.5% of children 5 and below have VAD (Maziya-Dixon et al 2006). Globally the deficiency affects between 75 to 250 million preschool children (World Health Organisation 1995). VAD causes blindness (Sommer et al 1995) and weakens the immune system (Semba et al 1999). Therefore, developing novel foodstuffs such as Golden Rice can tackle the nutritional problem caused by climate change and ensure food security.

Sustainable Intensification is a method of crop production attempting to increase yields without adverse environmental impact and the cultivation of more land (Baulcombe et al 2009). This method aims to combine genetic, ecological and socio-economic practices to safeguard food security despite the effects of climate change. An example of a genetic innovation would be breeding in the enzyme nitrogenase into cereals (Rogers and Oldroyd, 2014). This would improve the crop’s use of nitrogen, similar to how leguminous plants carry out nitrogen fixation.

By using these innovations, we our giving ourselves the best chance in the future to maintain food security despite unknown changes in climate including environmental stresses.

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References:

Ainsworth & Long. (2005) What have we learned from 15 years of free-air CO2 enrichment (FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2. New Phytologist 165: 351-372
Baulcombe, D., Crute, I., Davies, B., Dunwell, J., Gale , M., Jones, J., Pretty, J., Sutherland, W. and Toulmin, C., (2009) Reaping the benefits: science and the sustainable intensification of global agriculture. Report. The Royal Society pp72.
Busie B. Maziya-Dixon, Isaac O. Akinyele, Rasaki A. Sanus, Tunde E. Oguntona, Sagary K. Nokoe, and Ellen W. Harris (2006), Vitamin A Deficiency Is Prevalent in Children Less Than 5 y of Age in Nigeria, The Journal of Nutrition, vol. 136 no. 8 2255-2261
Peng S, et al,(2004)Rice yields decline with higher night temperature from global warming. Proc Natl Acad Sci USA,;101(27):9971–9975.
Rogers C Oldroyd GED.(2014). Synthetic biology approaches to engineering the nitrogen symbiosis in cereals. Journal of Experimental Botany 65, 1939–1946
Rosenzweig,(2014),Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison, Proc Natl Acad Sci U S A; 111(9): 3268–3273
Semba RD et al (1999) Vitamin A and immunity to viral, bacterial and protozoan infections. Proc Nutr Soc.;58:719–27.
Sommer A et al (1995). Vitamin A deficiency and its consequences: a field guide to detection and control. 3rd ed. Geneva: World Health Organization;. p. 69.
World Health Organization. (1995),The global prevalence of vitamin A deficiency: micronutrient deficiency information system (MDIS) working Paper 2: WHO/NUT/95 3. Geneva (Switzerland)



Popeye didn’t cause the spinach shortage: why the effects of global environmental change on plant function is a double-edge sword

Posted on by Anonymous

Climate change – a myth? We have all heard of it and its impending threat to our global environment. However, what we should ask ourselves is how are plants affected by our planet’s increasing temperatures, carbon dioxide (CO2) levels and the increasing frequency and intensity of severe weather changes?

Diagram illustrating some factors mentioned that are linked to climate change and their impact on several biological processes carried out in plants
Diagram illustrating some factors mentioned that are linked to climate change and their impact on several biological processes carried out in plants (Source: (Kallarackal and Roby, 2012))

Plants play a critical role in pulling CO2 out of the atmosphere. This uptake of CO2 during photosynthesis is a major pathway by which carbon can be stored (Tkemaladze and Makhashvili, 2016). Carbon dioxide is predicted to increase to approximately 1000 ppm by 2100. Since the beginning of the Industrial Revolution approximately 200 years ago average global temperatures have increased by 0.85°C and by the end of the century temperature is projected to rise by approximately another 4°C (IPCC, 2013).  Some would assume this to be beneficial to plants due to these warmer temperatures and increased levels of gas as it should, in theory, encourage growth. However, it is not as straight forward as this.

The enzyme rubisco is the key to this photosynthetic process by fixing CO2. Drake et al. (1997) states that the increased levels of CO2 will allow greater fixation by plants and, therefore, result in increased growth. However, Bisgrove and Hadley (2002) found that long-term exposure to elevated levels of CO2 caused an accumulation of carbohydrates in plant tissues, which in turn reduced the rate of photosynthesis. Furthermore, although plants initially respond positively to increasing temperature, this will eventually plateau or even decline after reaching the optimum range for some species. Plants may experience an increased rate of respiration leading to death; illustrating the world’s plants can easily lose their ability to act as a global carbon sink, becoming instead yet another carbon source (Mellilo et al., 1990; Hawkins et al., 2008).

Moreover, another consequence of global environmental change is a change to global weather patterns. Many do not connect climate change with uncharacteristic weather events, however, there is no doubt that climate change affects their intensity and frequency. Thus, in the future, we can expect to experience more frequent periods of drought, floods and storms (Frich et al., 2002). For example, during the past winter, there was snow escape in Spain as we witnessed a window to our future in the form of the courgette and spinach crisis, which caused havoc and rationing in British supermarkets. Yet these changing weather patterns will have a much larger impact than just a blow to spiralizer sales.

 

The heavy snowfall the province of Murcia in Spain experienced this winter ruining many crops.
The province of Murcia in Spain experienced heavy snowfall this winter ruining many crops (Source:http://edition.cnn.com/2017/02/03/europe/lettuce-shortage-europe/)

Stated above are only a few effects global climate change has on our planet’s plants. Plants have an essential regulatory role in the control of our planet’s climate: they did yesterday, they do today and they most certainly will in the future. If we continue to allow the CO2 level to increase at the rate it is currently we will suffer dramatic consequences. It not only will affect the Earth’s vegetation such as forests and plants, but will also have a knock-on effect on global food production, therefore, affecting our wellbeing.

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References

Bisgrove, R. and Hadley, P. (2002). Gardening in the global greenhouse: The impacts of future landuse and climate on the red list status of the Proteaceae in the cape floristic region, South Africa. Global Change Biology, 69, pp.79-91.

Drake, B., Gonzàlez-Meler, M. and Long, S. (1997). More efficient plants: A Consequence of Rising Atmospheric CO2?. Annual Review of Plant Physiology and Plant Molecular Biology, 48(1), pp.609-639.

Frich, P., Alexander, L., Della-Marta, P., Gleason, B., Haylock, M., Klein Tank, A. and Peterson, T. (2002). Observed coherent changes in climatic extremes during the second half of the twentieth century. Climate Research, 19, pp.193-212.

Hawkins, B., Sharrock, S. and Havens, K. (2008). Plants and climate change; which future? Richmond, UK: Botanic Gardens Conservation International, pp.98.

IPCC (2013) Climate Change 2013: The Physical Science Basis.Intergovernmental Panel on Climate Change, Cambridge, UK.

Kallarackal, J. and Roby, T. (2012). Responses of trees to elevated carbon dioxide and climate change. Biodiversity and Conservation, 21, pp.1327-1342.

Melillo, J., Callaghan, T., Woodward, F., Salati, E. and Sinha, S. (1990). Effects on Ecosystems, in Climate Change: The IPCC Scientific Assessment, edited by J. Houghton, G. Jenkins, J. Ephraums, Cambridge University Press, Cambridge, pp.283−310.

Tkemaladze, G. and Makhashvili, K. (2016). Climate changes and photosynthesis. Annals of Agrarian Science, 14, pp.119-126.



From global warming to global mourning: the effects of climate change on plants

Posted on by Anonymous

Ignore Trump, global warming is real. Climate change can be traced back to as early as 1896, where the Swedish chemist Svante Arrhenius first predicted human activities to affect atmospheric carbon dioxide (CO2) levels (NASA, 1998).

More than one hundred years on, Arrhenius is yet to be proved wrong.

Today, human-induced global change is taking many forms. From increased greenhouse gases to changes in global surface temperature, all species are under threat. The effects on plant functions are particularly important. After all, we need plants for our basic survival – try breathing or eating without them!

Greenhouse gases

Consistent with Arrhenius’ ideas, CO2 levels have increased drastically over the last 250 years (Ainsworth et al., 2008). Plants are dependent on CO2 for photosynthesis, where sunlight converts absorbed CO2 into sugar and oxygen. As carbon is extremely important in plants, forming 45% of their dry mass (Fangmeier et al., 2002), it can only be predicated that this increase will be beneficial to them, right?

An experiment looking at the responses of soybean to elevated CO2 concentrations shines a light on this idea. Results showed that plants were generally positively affected by elevated levels of CO2, shown by an increase in photosynthesis, water-use efficiency and biomass (Ainsworth et al., 2006).

So, what’s the problem with increased CO2? Fundamentally, elevated CO2 reduces the stomatal conductance in plants (the amount of CO2 entering the pore-like components of leaves) (Ainsworth et al., 2006). You may not believe it, but plants are cleverer than you think! A reduction in stomatal pores for gas exchange actually shows that plants are adapting to modern-day conditions by reducing their water loss and enhancing their survival (Beerling & Chaloner, 1993b).

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Figure 1. Stomata shown on the underside of a leaf.

Other than CO2, increased ozone (O3) also affects plant function. It ages them (a process called senescence, quite different from the old wrinkly plants your imagining), reduces their growth and yield (Fangmeier et al., 2002), and disturbs nutrient levels, shown in snapbeans (Tingey et al., 1986) for example.

Temperature

Oh, and there’s more: rising CO2 has led to a 0.76°C increase in global surface temperature since the 1800s (Ainsworth et al., 2008). With this comes disturbances in pollination timing, alongside increased drought disrupting conditions for efficient plant growth. This has been shown in Australia, where extreme temperature, drought and lowered sea levels resulted in severe mangrove “dieback” (The Guardian, 2017) (see full article here: https://www.theguardian.com/commentisfree/2017/mar/14/gulf-of-carpentarias-record-mangrove-dieback-is-a-case-study-of-extremes).

mangrove-image
Figure 2. The effect of global environment change on mangroves in Australia’s Gulf of Carpentaria.

What about in the long-term?

For plants: Despite the adaption of plants in the short-term, it is unknown how global change will affect them in the long run. However, a photosynthetic acclimation is expected, accompanied by higher carbohydrate concentrations, lower soluble proteins and inhibition of photosynthetic capacity (Drake et al., 1997).

For humans: Plant function and agricultural systems are tightly interlinked, therefore the negative effects of global change could potentially lead to food insecurity. With an estimated 60% increase in global cereal demand by 2050 (Rosegrant and Cline, 2003), the understanding of future plant responses could shape the fate of humanity!

Word count: 490 words

References:

Ainsworth, E.A., Rogers, A. and Leakey, A.D., 2008. Targets for crop biotechnology in a future high-CO2 and high-O3 world. Plant physiology, 147(1), pp.13-19.

Ainsworth, E.A., Rogers, A., Vodkin, L.O., Walter, A. and Schurr, U., 2006. The effects of elevated CO2 concentration on soybean gene expression. An analysis of growing and mature leaves. Plant Physiology, 142(1), pp.135-147.

Beerling, D.J. and Chaloner, W.G., 1993. The impact of atmospheric CO2 and temperature changes on stomatal density: observation from Quercus robur lammas leaves. Annals of Botany, 71(3), pp.231-235.

Drake, B.G., Gonzàlez-Meler, M.A. and Long, S.P., 1997. More efficient plants: a consequence of rising atmospheric CO2?. Annual review of plant biology, 48(1), pp.609-639.

Fangmeier, A., De Temmerman, L., Black, C., Persson, K. and Vorne, V., 2002. Effects of elevated CO 2 and/or ozone on nutrient concentrations and nutrient uptake of potatoes. European Journal of Agronomy, 17(4), pp.353-368.

NASA., 1998. Global Warming. TAPPI JOURNAL.

Rosegrant, M.W. and Cline, S.A., 2003. Global food security: challenges and policies. Science, 302(5652), pp.1917-1919.

The Guardian. (2017). Gulf of Carpentaria’s record mangrove dieback is a case study of extremes. [online] Available at: https://www.theguardian.com/commentisfree/2017/mar/14/gulf-of-carpentarias-record-mangrove-dieback-is-a-case-study-of-extremes [Accessed 19 Mar. 2017].

Tingey, D.T., Rodecap, K.D., Lee, E.H., Moser, T.J. and Hogsett, W.E., 1986. Ozone alters the concentrations of nutrients in bean tissue (No. PB-88-149133/XAB; EPA-600/J-86/431). Environmental Protection Agency, Corvallis, OR (USA). Environmental Research Lab..



Green Invasion on the Arctic Tundra

Posted on by Isabelle Mills

As the 24-hour summer sun melts the long winter snow, a flush of green emerges from the cold, frozen landscape. In recent years unexpected visitors have migrated into the harsh environment that 50 years ago would have succumbed to the cold. Rising global temperatures and atmospheric carbon dioxide (CO2), particularly since the turn of the millennia, is allowing shrubs and spruce (Reid, n.d.) found further south in boreal forests to survive the new tundra conditions.

This is a typical Tundra environment during the summer period. The soil is either permanently or semi-permanently frozen and the vegetation is dominated by mosses, lichens and grasses that clump together to withstand the strong cold winds. In the winter temperatures average -34C and in the summer 3-12C (NHPTV.org, 2017).
This is a typical Tundra environment during the summer period. The soil is either permanently or semi-permanently frozen and the vegetation is dominated by mosses, lichens and grasses that clump together to withstand the strong, cold winds. In the winter temperatures average -34 degrees Celsius and in the summer 3-12 degrees Celsius (NHPTV.org, 2017).

The effect of modern humans’ industrial activity discharging Carbon Dioxide (CO2) into the atmosphere has caused the average global temperature to rise 0.99 °C relative to 1951-1980 figures (NASA, 2017). Due to the nature of the environment, Arctic regions are more sensitive and experience the warming effect two to three degrees higher than the global average (Ramsayer, 2016).

The combination of increased CO2, higher temperatures, and subsequently longer growing seasons is in fact benefitting some vegetation.  Satellite images have shown a 29.4 percent increase of greening in the far north of Russia, Scandinavia, Alaska and Canada where previously only limited vegetation could grow (Ramsayer, 2016). However, as with all dramatic changes there are winners and loser and many mosses and lichens have been declining.

Here we can see the encroachment of the boreal forest treeline on the tundra environment. Species include Black Spruce (Picea mariana). Though the trees are sparsely located and thin, it highlights how the ecosystem is becoming more habitable to a new range of vegetation (Goldstone, 2013).
Here we can see the encroachment of the boreal forest treeline on the tundra environment. Species include Black Spruce (Picea mariana). Though the trees are sparsely located and thin, it highlights how the ecosystem is becoming more habitable to a new range of vegetation (Goldstone, 2013).

There are multiple reasons for Arctic greening, one being increased temperature. When the temperature rises closer to its optimum growing temperature the rate of the chemical processes such a photosynthesis and enzymes function within the plant improves dramatically. The efficiency of photosynthesis (process of absorbing light energy to react with CO2 to produce sugars) improves because the quantity of photosynthetic pigments increases under warmer temperatures (Saxe et al., 2002). When exposed to temperatures above the optimum, it can cause proteins to become inactive, inhibiting CO2 fixation needed for photosynthesis (Shailes, 2013). This may be one of the reasons behind decline in the native mosses and lichens in the region.

Higher temperatures also create a longer growing season (previously 50-60 days) (Krajick, 2016) allowing the frozen soil to thaw. Species including Alder can now successfully compete as their seedlings are able to grow quickly allowing the roots to take hold and withstand frost cover at the end of the growing season.

Arctic Greening has also been influenced by rising CO2 acting as a fertiliser for plants in soils with a low moisture content. CO2 is a limiting factor in photosynthesis, with more readily available, photosynthesis can function more efficiently (Saxe et al., 2002). Studies have shown that plants have the ability to photosynthesise up to 40 percent faster when they are subjected to CO2 concentrations between 475 and 600ppm (Pearson et al., 2013).

The Arctic region of interest covers an area of 10 million square miles. The average rate of greening has been identified as 29.4%. Some areas highlighted in green and blue showed a percentage growth of 34-41%. The areas identified in orange and red experienced a decrease in greening by 3 to 5%. These images were developed from the information gathered by MODIS satellite instruments (Hansen et al., 2013).
The Arctic region of interest covers an area of 10 million square miles. The average rate of greening has been identified as 29.4%. Some areas highlighted in green and blue showed a percentage growth of 34-41%. The areas identified in orange and red experienced a decrease in greening by 3 to 5%. These images were developed from the information gathered by MODIS satellite instruments (Hansen et al., 2013).

Temperatures are expected to rise alongside CO2 concentrations, inevitably changing the structure of the Arctic region and enhancing the greening effect leading to further warming. This will cause further encroachment of the treeline and a decline in mosses and lichens which will in turn alter the ecosystem relationships and dynamics between plant and animal species (Pearson et al., 2013).

 

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In Text References: 

Krajick, K. (2016). Where Trees Meet Tundra, Decoding Signals of Climate Change. [Blog] State of the Planet. Available at: http://blogs.ei.columbia.edu/2016/11/16/where-trees-meet-tundra-decoding-signals-of-climate-change/ [Accessed 16 Mar. 2017].

NASA. (2017). Climate Change: Vital Signs of the Planet. [online] Available at: https://climate.nasa.gov/vital-signs/carbon-dioxide/ [Accessed 17 Mar. 2017]. [Accessed 18 Mar. 2017].

Pearson, R., Phillips, S., Loranty, M., Beck, P., Damoulas, T., Knight, S. and Goetz, S. (2013). Shifts in Arctic vegetation and associated feedbacks under climate change. Nature Climate Change, 3(7), pp.673-677.

Ramsayer, K. (2016). NASA Studies Details of a Greening Arctic. [Blog] NASA. Available at: https://www.nasa.gov/feature/goddard/2016/nasa-studies-details-of-a-greening-arctic [Accessed 20 Mar. 2017].

Reid, R. (n.d.). Explore the World’s Tundra. [online] National Geographic. Available at: http://www.nationalgeographic.com/environment/habitats/tundra-biome/ [Accessed 19 Mar. 2017].

Saxe, H., Cannell, M., Johnsen, Ø., Ryan, M. and Vourlitis, G. (2002). Tree and forest functioning in response to global warming. New Phytologist, 149(3), pp.369-399.

Shailes, S. (2013). It’s getting hot out here: the challenges facing plants in hot weather. [Blog] Plant Scientist. Available at: https://plantscientist.wordpress.com/2013/07/23/its-getting-hot-out-here-the-challenges-facing-plants-in-hot-weather/ [Accessed 16 Mar. 2017].

 

Image References:

Goldstone, H. (2013). Dramatically Greener Arctic in Near Future. [Blog] Capean Islands. Available at: http://capeandislands.org/post/new-research-predicts-dramatically-greener-arctic-near-future#stream/0 [Accessed 19 Mar. 2017].

Hansen, K., Cole, S. and Mariaire, R. (2013). NASA – Amplified Greenhouse Effect Shifts North’s Growing Seasons. [online] NASA. Available at: https://www.nasa.gov/topics/earth/features/growth-shift.html [Accessed 19 Mar. 2017].

NHPTV.org. (2017). Tundra. [online] Available at: http://www.nhptv.org/wild/tundra.asp [Accessed 21 Mar. 2017].

 

 



Old Macdonald Overfarmed: How Increasing Global Agriculture leads to Deforestation

Posted on by Kieran Woof

The Rainforests are taking the hit from our need to eat…

Almost anyone could tell you that the world’s population is increasing – and rapidly so. Naturally, this requires us to produce more and more food with which to supply all of these new faces.

However, the constant expansion of farms leads to the constant decline of forest areas, which in turn causes detrimental effects on our environment as a whole. The main region affected by these practices is the Amazon Rainforest, well known for housing around half of all the species in the entire world, as well as acting as one of Earth’s biggest Carbon sinks.

This means that its destruction will lead to a huge reduction in biodiversity, as well as releasing vast amounts of trapped Carbon Dioxide into the atmosphere, which then contributes to Global Warming. As well as the pollution aspect, deforestation may also lead to the total extinction of many tree species. This may be caused by directly chopping these trees down, or by the reduction in animals which disperse the seeds, via eating the fruit they produce (Montoya, 2008).

Image result for rainforest deforestation for farming
Farmland is rapidly encroaching on our planets forested areas (Source: Emaze)

So how big is the problem?

It has been estimated that around 350 Million Hectares of Tropical Rainforest has been converted for other land use. (Lal, 2008) Furthermore, 91% of all land deforested in the Amazon since 1970 has been used for livestock pasture! (FAO, 2006). By Converting this land, not only are we losing trees in the long term, but we are also inhibiting their possible reintroduction. This is because the soil cleared for farming often rapidly degrades due to reduced stability and intense rainfall (Kibblewhite, 2008)

The problem here is that we cannot allow people to go without food in order to save our planet’s trees. What needs to change instead is the farming technique. In farm areas bordering rainforests, the method of farming is much more likely to be expansive rather than intensive (López-Carr, 2013). This essentially means that farmers focus on growing as much of the crop as possible, rather than trying to obtain more successful growth from a smaller patch. Essentially, this leads to a lot of land being wasted, with neither tropical forests or crops actually growing on it!

So what does the Future Hold?

However, there are reasons to be optimistic! A key success story in attempts to reduce deforestation, whilst keeping high crop production, is seen in the Soybean industry. This used to be seen as a major detrimental industry to the Amazon Rainforest. However, following boycotts from several large companies, a 2015 study showed that only around 1% of all soybean production had come as a result of deforestation, despite the industry expanding over 1.3 million hectares! (Garrett, 2016).

The Soybean – An unlikely success story (Source: Plant Village)

If this technique can be implemented for other farmland crops, then we can hopefully provide enough food to keep the growing population fed, as well as protecting one of the worlds most important ecological areas.

(Word Count – 485)

References

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS . (2006). Livestock’s Long Shadow: Environmental issues and Problems.

Garrett, R, Rausch, L. (2016). Green for gold: social and ecological tradeoffs influencing the sustainability of the Brazilian soy industry. The Journal of Peasant Studies. 43 (2)

Kibblewhite, M.G, Ritz, K, Swift, M.J. (2008). Soil health in agricultural systems. Philosophical Transactions of the Royal Society B: Biological Sciences. 363 (1492), 685-701.

Lal, R. (2008). Carbon Sequestration. Philosophical Transactions of the Royal Society B: Biological Sciences. 363 (1492), 815-830.

López-Carr, D, Burgdorfer, J. (2013). Deforestation Drivers: Population, Migration, and Tropical Land Use. Environment. 55 (1)

Montoya, D. (2008). Habitat loss, dispersal, and the probability of extinction of tree species. Communicative and Integrative Biology. 1 (2), 146-147.



Bloom and Bust

Posted on by Lauren Furmidge
‘Blue Marble’ –Earth as seen by Apollo 17 (NASA/ Apollo 17 Crew, 1972)

 

In 1972, one of the most iconic photographs of the Earth was taken from space.  The ‘Blue Marble’ snapped by the astronauts aboard Apollo 17 shows an Earth with deep blue oceans but very little greenery on the land. Now photographs of the Earth from space look very different, with luscious green patches where there was once dull brown.  The spreading and growing of green vegetation is a result of rising CO2 levels in the Earth’s atmosphere.  The Earth has undergone an increase of 18 square kilometres of new vegetation between 1982 and 2009 (Keenan et al., 2016).

 

Since the Industrial Revolution, the burning of fossil fuels such as coal and oil by humans has caused an enormous rise in atmospheric CO2 from 280ppm to over 400ppm today, inducing disastrous effects on the environment such as climate change (Khatiwala et al., 2009).

So if increases in CO2 are so bad, why is a boom in plant growth occurring?

 

Plants use CO2 in photosynthesis; a process in which plants use CO2, water and light from the sun to produce sugars for growth and oxygen which they give off.  The increased rates of photosynthesis are down to a chemical called Rubisco, which helps incorporate CO2 into the photosynthesis process.  Rubisco first evolved long, long ago- far before humans began affecting the world.  At this point in history CO2 levels were much greater than during recent times.  This means that Rubisco is less efficient at lower CO2 levels.  As humans have begun to disturb these lower CO2 concentrations and caused them to rise, Rubisco works better meaning plants are able to photosynthesise at a greater rate, which increases their growth (Taylor et al., 1994).

 

Sun through leaves (Shuttershock, 2013)
Sun through leaves (Shuttershock, 2013)

 

Although this appears to be all good news for the plants, rising atmospheric CO2 levels also bring negative effects, one of them being climate change.  With increasing CO2 comes increases in temperature which can negatively impact plants.  Plants require an optimum temperature in order to survive well and if they are not able to shift their ranges, they will suffer the effects of warmer, dryer environments which are ultimately inhospitable (Hatfield and Prueger, 2015).  So whilst plants prosper in the short term, when temperatures get too high they languish.

Also, there is evidence that rising CO2 reduces the ability of stomata- small pores on plants- to conduct CO2 and perform transpiration- the removal of water-, ultimately leading to reduced photosynthesis (Drake et al., 1997).

 

Although rising CO2 has turned the brown swathes of Earth captured in the ‘Blue Marble’ into luscious green, behind this initial bloom lurks an ominous truth. If humans continue to fuel rising CO2 levels, plants will suffer and food crops will fail. Global temperature increases, rainfall changes and extreme weather events- droughts and floods- jeopardise the functions of plants, ultimately devastating them.

 

Word Count: 468

 

 

References

Drake, B.G., Gonzalez-Meler, M.A., Long, S.P.,1997. More efficient plants: a consequence of rising atmospheric CO? Annu. Rev. Plant Physiol. Plant Mol. Biol. 48, 609 – 639.

Hatfield, J.L. and Prueger, J.H., 2015. Temperature extremes: effect on plant growth and development. Weather and Climate Extremes, 10, pp.4-10.

Keenan, T.F., Prentice, I.C., Canadell, J.G., Williams, C.A., Wang, H., Raupach, M. and Collatz, G.J., 2016. Recent pause in the growth rate of atmospheric CO2 due to enhanced terrestrial carbon uptake. Nature communications, 7.

Khatiwala, S., Primeau, F. and Hall, T., 2009. Reconstruction of the history of anthropogenic CO2 concentrations in the ocean. Nature, 462(7271), pp.346-349.

NASA/ Apollo 17 Crew., 1972., ‘Blue Marble’ –Earth as seen by Apollo 17. [Photograph]

Shuttershock., 2013., Sun through leaves. [Photograph]

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(Special Issue), pp.1761-1774.

 

 



Could Climate Change STARVE us?

Posted on by Anonymous

The planet needs YOUR help!

We all have been alarmed and warned about rising sea temperatures, melting sea ice and glaciers, but the main problem is that we could describe them on and on.. Therefore, one of the greatest challenges the earth faces in this day and age is CLIMATE CHANGE.

A photo to show the loss of vegetation as a result of climate change (http://ayalim.org/israeli-plant-species-resistant-to-climate-change/)
A photo to show the loss of vegetation as a result of climate change  Available at:(http://ayalim.org/israeli-plant-species-resistant-to-climate-change/)

An unprecedented ↑ in atmospheric CO2 and temperature can shockingly lead to:

  • Species extinction
  • Collapsing ecosystems and food chains and as a result, foreseeable shortages of food and water to the increasing global population.

One of the toughest tasks this century, is predicting the response of plants to global climate change. Thus, what is essentially happening to our plants through this unpredictable change?

Many studies have observed:

Plants will thrive with an established elevation in CO2 and temperature…

  • As more CO2 = more fixation = more photosynthesis

Bisgrove and Hadley (2002) suggest that a “doubling in carbon dioxide level can increase plant growth by as much as 50%”

  • More heat = advanced growth and seed germination

 

HOWEVER…

Agriculture sustains almost all life-forms on Earth, meaning adverse conditions, can restrict crop plants in reaching their full genetic potential of producing a high yield (Anjum et al., 2014).

(1) Heat waves, extreme temperature events are projected to become more intense, more frequent and longer lasting to what is currently been observed in recent years (Hatfield and Prueger, 2015). Consequently, when a drought occurs where the levels of heat are extreme, the growth of a plant will rapidly decrease due to the high level of moisture loss. Furthermore, although water is essential for the functioning of virtually every plant on the planet, too much water (as a result of a storm… which we all can undeniably find exciting!) can in fact reduce the amount of oxygen in the soil, making a plant more susceptible to disease.

NOTE: Remember to stop and think, ‘this storm is not only damaging our plants, but in fact our livelihoods!’

(2) In addition, there is abundant evidence that in the long term, plants will begin to acclimate to a rise in CO2 levels. Therefore, the photosynthetic capacity becomes inhibited due to the plants being unable to utilise the additional carbohydrate that is accompanied with photosynthesis (Drake et al., 1997).

(3) Shockingly, crops of the future that are grown in a high- CO2 environment, will have decreases in the concentrations of zinc, iron and protein in grains of wheat, barley and rice (Myers et al., 2014) meaning the food in which we eat will be much less nutritious. Considering most people depend on these grains for their source of zinc and iron this can be detrimental to human health.

percentage
A graph to show the result in % reduction of nutrients from certain crops in an expected level of CO2 by 2050. (Source: NATURE)

 

If we continue to actively contribute to a world of increasing CO2 and temperature, not only are the plants on our Earth disturbed but if you stop and think: YOU yourself can be hugely affected.

A question of thought, who knows what this may cause to our future health and livelihoods?

 

 

References:

  • Anjum, N., Gill, S. and Gill, R. (2014). Plant adaptation to environmental change. 1st ed. Wallingford: CABI.
  • Bisgrove, R. and Hadley, P. (2002) Gardening in the Global Greenhouse: The Impacts of Climate Change on Gardens in the UK. Technical Report. Oxford: UKCIP.
  • Drake, B., Gonzalez-Meler, M. and Long, S. (1997). MORE EFFICIENT PLANTS: A Consequence of Rising Atmospheric CO2?. Annual Review of Plant Physiology and Plant Molecular Biology. 48(1), pp.609-639.
  • Hatfield, J. and Prueger, J. (2015). Temperature extremes: Effect on plant growth and development. Weather and Climate Extremes, 10, pp.4-10.
  • Myers, S., Zanobetti, A., Kloog, I., Huybers, P., Leakey, 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(7503), pp.139-142.

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What can an Egyptian King tell us about climate change?

Posted on by Carla Broom

Our plants are hugely affected by carbon dioxide levels in our atmosphere. Green plants absorb CO2 to produce sugars for growth (and oxygen for us!) in a process known as photosynthesis, meaning CO2 levels can hugely affect plant function.

All green flowers take in carbon dioxide and convert it to sugars and oxygen
All green plants absorb CO2 and produce sugars and oxygen

CO2 levels are currently at 406 parts per million (ppm), which may not seem high, but have risen 21% over the last 230 years (Woodward, 1987). This fluctuated constantly throughout time, varying from 280 to 370ppm over the last 24 million years (Van Der Burgh et al, 1993), but now for the first time exceeds 400ppm (Khatiwala et al, 2009).

CO2, oxygen and water are absorbed and released through small pores on the underside of leaves known as stomata, protected by guard cells which open and close the pore. This is affected by conditions such as hormones, light, and- you guessed it- atmospheric CO2 concentration. Stomata allow plants to survive stress, for example retaining water during extreme heat and drought (Hetherington & Woodward, 2003).

Microscope image of two kinds of stomata on the underside of leaves
Microscope image of stomata on the underside of leaves (Hetherington & Woodward, 2003)

How do we investigate change in stomata over time? We can find out what plants were like thousands of years ago- that’s where the Egyptian King Tutankhamun comes in. Olive leaves from his tomb (from 1327 BC) were taken, and the amount of stomata on the underside counted and compared to Egyptian olive samples from 332BC, 1818AD, 1978AD and 1991AD (Beerling & Chaloner, 1993a).

The tomb of King Tutankhamun, with ancient olive leaves around the headpiece
The tomb of King Tutankhamun, with olive leaves around the headpiece (Beerling & Chaloner, 1993a).

As CO2 increases, the number of stomata decrease (Beerling & Chaloner, 1993a). This is also seen in other species, such as oak (Van der Burgh et al, 1993) and pine (Van de Water et al, 2007), but their methods weren’t as creative! The first ever study to show this change found a 40% decrease in number of stomata over the last 230 years (Woodward, 1987).

Why does this happen? CO2 affects the genetic make-up of plants, reducing the number of cells developing into stomata. Plants are likely adapting to rising temperatures and CO2 levels by decreasing the amount of pores to reduce water loss, improving their water use efficiency (Beerling & Chaloner, 1993b).

Is this change a problem for plants? The short term effects of more CO2 can be beneficial, increasing photosynthesis and growth and therefore  yield (Osborne et al, 1997), however the long term effects are not so good. Fewer stomata decreases CO2 uptake, reducing growth and leading to higher atmospheric CO2 (Reddy et al, 2004). Although the plants retain more water, if CO2 levels and temperature decrease again, plants with fewer stomata will have reduced water use efficiency (Woodward, 1987) as they will not be able to exchange as well. Less sugar production also reduces metabolism, therefore CO2 intake is inhibited even further (Flexas & Medrano, 2002) in a cycle known as negative feedback; a reduction in one factor causes a further reduction in something else.

This shows us that plants have changed greatly over thousands of years to adapt to the increasing carbon dioxide levels around them, which could have long-term negative effects on both plants and other life. The environment around us is changing with the atmosphere, and human-caused CO2 increase should not be ignored as it affects many things, no matter how small.

Word Count: 469

 

References

Beerling, D. J., Chaloner, W. G. 1993 a. Stomatal Density Responses of Egyptian Olea europaea L. Leaves to CO2 Change to 1327BC. Annals of Botany, 71: 431-435

Beerling, D. J., Chaloner, W. G. 1993 b. Evolutionary Responses of Stomatal Density to Global CO2 Change. Biological Journal of the Linnean Society, 48: 343-353

Flexas, J., Medrano, H. 2002. Drought Inhibition of Photosynthesis in C3 Plants: Stomatal and non-Stomatal Limitations Revised. Annals of Botany, 89(2): 183-189

Hetherington, A. M., Woodward, F. I. 2003. The Role of Stomata in Sensing and Driving Environmental Change. Nature, 424: 901-908

Khatiwala, S., Primeau, F., Hall, T. 2009. Reconstruction of the History of Anthropogenic CO2 Concentrations in the Ocean. Nature, 462: 346-350

Osborne, C. P., Drake, B. G., LaRoche, J., Long, S. P. 1997. Does Long Term Elevation of CO2 Concentration Increase Photosynthesis in Forest Floor Vegetation? (Indiana Strawberry in a Maryland Forest). Plant Physiology, 114(1): 337-344

Reddy, A. R., Chaitanya, K. V., Vivekanandan, M. 2004. Drought-Induced Responses of Photosynthesis and Antioxidant Metabolism in Higher Plants. Journal of Plant Physiology, 161(11): 1189-1202

Van Der Burgh, J., Visscher, H., Dilcher, D., Kürschner, W. M. 1993. Paleoatmospheric Signatures in Neogene Fossil Leaves. Science, 260(5115): 1788-1790

Van de Water, P. K., Leavitt, S. W., Betancourt, J. L. 2007. Trends in Stomatal Density and 13C/12C Ratios of Pinus flexilis Needles During the last Glacial-Interglacial Cycle. Science, 264: 239-243

Woodward, F. I. 1987. Stomatal Numbers are Sensitive to Increases in CO2 from pre-Industrial Levels. Nature, 327: 617-618



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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Roads Reduce Role of Rainforests

Posted on by Anonymous

Rainforests are considered ‘the finest celebration of nature ever known on the planet’ yet increasing pressure to develop new roads for economic growth is their biggest threat.

Tropical rainforests cover 2-7% of Earth. They support 170,000 plant species. Their small area but tremendous biodiversity makes them global hotspots for conservation funds.

High levels of rainfall and constantly high temperatures creates a unique habitat. Many trees packed closely together creates a closed canopy. As a result, the rainforest is dark and humid. There is lower light, wind and temperatures as a result that species need to be specially adapted to in order to thrive (Laurance et al. 2009).

New developments threaten this structure. Species can either respond and adapt to new conditions or face the risk of extinction.

Rainforests are especially vulnerable to economic pressures. Roughly 2.5 million hectares (25,000km2) of the Brazilian Amazon are lost every year through deforestation. Economic growth is often the main driver for habitat loss. If the current rates continue, within 50 years, global rainforests are likely to be lost forever.

Many activities lead to deforestation but roads are seen as especially detrimental (Figure 1). Opportunities for logging, oil and mining often drive the development of new roads (Goosem 2007). Previously untouched areas are now accessible via roads and are now vulnerable to widespread biodiversity loss (Brudvig et al. 2015; Haddad et al. 2015).

Figure 1. New roads create barriers between previously connected species. Barriers for reproduction and pollination ultimately lead to species loss.
Figure 1. New roads create barriers between previously connected species. Barriers for reproduction and pollination ultimately lead to species loss.

The issue is not only minor access roads but large highways built for an increasingly urban world. The Trans-Amazonian Highway in Brazil is 4000km. This only makes it the third longest highway in Brazil (Figure 2).

Destruction of the rainforest is therefore a primary cause of plant biodiversity loss. Roads will change rainforest habitats from large and pristine to small and isolated. New edges are created alongside roads. Species are impacted more than this than widespread deforestation. This process of habitat fragmentation creates smaller, isolated populations and plant species are lost (Linert 2004; Gossem et al. 2011; Weiner et al. 2014).

Figure 2. Trans-Amazonian Highway is among one of many road developments through tropical rainforests that result in widespread deforestation and loss of important plant species that play vital roles in regulating carbon dioxide levels on Earth.
Figure 2. Trans-Amazonian Highway is among one of many road developments through tropical rainforests that result in widespread deforestation and loss of important plant species that play vital roles in regulating carbon dioxide levels on Earth.

Overall, trees lost from the rainforest allows light to reach the ground that was not able to before. Shade preferring species are no longer the best suited. Those plants that thrive on more light become more successful (Laurance et al. 2009). Species that were one dominant no longer are.

These changes to the surrounding environment impact important interacting species. Smaller patches with different conditions attract fewer plant species and therefore fewer pollinators. Pollinating species are likely to decline as a result, threatening their own survival and that of the plants (Aguilar et al. 2006).

If reproductive output declines, the number of species surviving to continue the population declines. The negative cycle continues until a whole species is extinct. Community structure is altered and important interactions are lost.

Each plant species, rare or common, plays an important role in regulating carbon, purifying water and stabilising soil qualities. Loss of species variety creates areas that are extremely similar. Soon, rainforests will lose their functional role and contribute less to the global system.

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REFERENCES

Aguilar, R., Ashworth, L., Galetto, L. & Aizen, M. A. (2006) Plant reproductive susceptibility to habitat fragmentation: review and synthesis through a meta-analysis. Ecology Letters, 9, 968-980.

Brudvig, L. A., Damschen, E. I., Haddad, N. M., Levey, D. J. & Tewksbury, J. J. (2015) The influence of habitat fragmentation on multiple plant-animal interactions and plant reproduction. Ecology, 96, 2669-2678.

Cunningham, S. A. (2000) Effects of habitat fragmentation on the reproductive ecology of four plant species in mallee woodland. Conservation Biology, 14, 758-768.

Goosem, M. (2007) Fragmentation impacts caused by roads through rainforests. Current Science, 93, 1587-1595.

Haddad, N. M., Brudvig, L. A., Clobert, J., Davies, K. F., Gonzalez, A., Holt, R. D., Lovejoy, T. E., Sexton, J. O., Austin, M. P., Collins, C. D., Cook, W. M., Damschen, E. I., Ewers, R. M., Foster, B. L., Jenkins, C. N., King, A. J., Laurance, W. F., Levey, D. J., Margules, C. R., Melbourne, B. A., Nicholls, A. O., Orrock, J. L., Song, D. A. & Townshend, J. R. (2015) Habitat fragmentation and its lasting impact on Earth’s ecosystems. Sci. Adv.

Laurance, W. F., Goosem, M. & Laurance, S. G. W. (2009) Impacts of roads and linear clearings on tropical forests. TREE, 1149, 1-11.

Lienert, J. (2004) Habitat fragmentation effects on fitness of plant populations – a review. Journal for Nature Conservation, 12, 53-72.

Weiner, C. N., Werner, M., Linsenmair, K. E. & Bluthgen, N. (2014) Land-use impacts on plant-pollinator networks: interaction strength and specialisation predict pollinator declines. Ecology, 95, 466-474.