This post is a lot later than most of my other posts. It's been an interesting three month blogging jourey for me, as I've learned more about the links between climate and our society in general. I ended up on a tangent and explored more in terms of food security. I found this part particularly challenging as I've never thought about the complexities of food security, as well as how our climate influences it. My blogging journey meant I had to re-visit the nitrogen cycle, one that I haven't really thought about since leaving high school.
My favorite part of my blogging journey was my post on capitalism. Capitalism has been a topic we've touched on in GEOG2010, and subsequently in GEOG3072. I brought this topic into my blog because I realized despite how much we talk about anthropogenic influences on the environment, rarely do we talk about its main root cause: capitalism.
I didn't end up quite answering my questions I set at the beginning of my blogging journey, namely because my interests started to shift, as well as realizing that health is such a big topic that is merely impossible to cover due to its many facets. I hoped from my blogging journey that I would be more optimistic about the future of climate change, but looking at the COP21 agreement in depth has challenged my optimism and rather made me quite pessimistic and critical of these agreements. I realized these international agreements are more complex, and the challenge of meeting these targets are no longer a blame game, but only achievable with co-operation and conversation.
However, I leave a little more optimistic that because people are starting to realize how climate change impacts our healths and not just our living environments, that climate action will be bigger in the future. I hope for a more agriculturally stable world, with a more Malthusian view on development. I hope you enjoyed my journey as much as I did.
Healthy Planet, Healthy People
Healthy Planet, Healthy People: the medically challenging future
Friday, 20 January 2017
Thursday, 8 December 2016
Geoengineering?
In my last post, I mentioned geoengineering in the form of carbon dioxide removal and solar radiation management. In this post, I will be exploring how geoengineering may impact agricultural productivity. In particular, I will be exploring solar radiation management.
Current climate change observations suggest an increase in average temperature, shown in the graph below. To combat rising mean surface temperatures, solar radiation management (SRM) has been suggested as a possible solution. SRM aims to reflect a proportion of the sun's rays away from Earth, by doing so stabilizing temperatures. This is done through methods such as space reflectors and stratospheric aerosols. It is seen as a cheap and effective method of stabilizing climate, as it can reduce mean temperatures within days, weeks, or months.
SRM has performed well in different models - for example, Govindasamy and Calderia (2000) used the Community Climate Model to show that it could reverse global annual mean warming. However, as Rach et al. (2008) have shown, SRM methods such as stratospheric sulphate aerosols, whilst effective in stabilizing temperature can also create changes in precipitation as well as 'contributing to the total global source of acid rain'.
To conclude this post, as hopeful I was about geoengineering possibly being the future for climate action, I now question whether it is possible in the first place as some countries will be negatively affected, as well as whether the WHO will allow this to go fowards. Of course, there are other methods of geoengineering that I have not covered, but I hope to do so after my assessment for this module is over.
My next post will summarize my blogging journey. I hope you have a lovely Christmas and a fantastic New Year. Thank you for being here with me on my knowledge journey.
Current climate change observations suggest an increase in average temperature, shown in the graph below. To combat rising mean surface temperatures, solar radiation management (SRM) has been suggested as a possible solution. SRM aims to reflect a proportion of the sun's rays away from Earth, by doing so stabilizing temperatures. This is done through methods such as space reflectors and stratospheric aerosols. It is seen as a cheap and effective method of stabilizing climate, as it can reduce mean temperatures within days, weeks, or months.
SRM has performed well in different models - for example, Govindasamy and Calderia (2000) used the Community Climate Model to show that it could reverse global annual mean warming. However, as Rach et al. (2008) have shown, SRM methods such as stratospheric sulphate aerosols, whilst effective in stabilizing temperature can also create changes in precipitation as well as 'contributing to the total global source of acid rain'.
Source: NASA |
In cases like these, I wonder whether SRM may impact agricultural production leading to changes in food security. I stumbled across Pongratz et al. (2012)'s paper on this very subject, where they found that SRM under climate models showed increase crop yield. The top panels show yield increases on different crops with SRM, in comparison to unmodified climate.
Source: Pongratz et al. (2012) |
However, what I found interesting was that this effect is not uniform across the globe. The study then looks into yield and crop production by geoengineering, this time separating it by latitude.
Source: Ibid |
The second figure suggests that regions will experience changes in crop productivity to varying extents, and thus may indicate changes in food security. I do wonder whether the regions that experience loss in agricultural productivity are compensated by those experiencing gains.
In this sense, I further question whether geoengineering will be a viable option in the future, because countries will not willingly put themselves at a loss. Additionally, SRM's impacts on agriculture in regions may create new geopolitical tensions especially if an area goes under famine. Furthermore, what happens if a region predicted to gain agricultural productivity does not deliver completely? Jamais Cascio suggests that an international body takes over to supervise geoengineering- but I am skeptical as international bodies does not guarantee tension-free food security. Therefore it does not come to me as a surprise when the UN extended the freeze on geoengineering based on the premise that we do not know its full impact on biodiveristy.
Pongratz et al. (2012)'s study indicates that a country with a massive population such as India, will experience losses in maize yields, but have increased rice, and wheat yields. In Yang et al. (2016)'s paper on Indian groundnuts, SRM has a huge impact by decreasing its yield up to 20%. Interestingly, they also found that once SRM is switched off, the yields slowly return back to normal with no statistical difference. I wonder if this could mean we could experiment with geoengineering to understand the implications for each country. But again, I don't believe geoengineering is a viable option anytime in the future, especially since it may negatively impact certain areas' agricultural productivity which threatens a nation's food security.
What I find quite odd is that within cost-benefit analysis of geoengineering, little about health is mentioned. To rectify this, Effiong and Neitzel (2016) investigates the health impacts of stratospheric aerosol from SRM. The two found that SRM is unjustifable given the direct health impacts such as respiratory weakening. The table below summarizes the main impacts. This study was terrifying for me, as there are so many insufficient data available when it comes to potential SRM aerosol interactions. Additionally, this study only looks into the direct impacts of inhaling these aerosols and I wonder if health effects will worsen through indirect means as well.
Source: Effiong and Neitzel (2016) |
To conclude this post, as hopeful I was about geoengineering possibly being the future for climate action, I now question whether it is possible in the first place as some countries will be negatively affected, as well as whether the WHO will allow this to go fowards. Of course, there are other methods of geoengineering that I have not covered, but I hope to do so after my assessment for this module is over.
My next post will summarize my blogging journey. I hope you have a lovely Christmas and a fantastic New Year. Thank you for being here with me on my knowledge journey.
Friday, 2 December 2016
COP21 Part 3
This is my last post on COP21. I realized there were other parts of the agreement I did not agree with, but there was one aspect that really struck me as central to climate action - the necessity for legally binding agreements.
The lack of legally binding-ness, is another problem highlighted by many others. It is not mentioned in the agreement at all (or rather, it is phrased as 'partly legally binding and partly voluntary'), and without any consequences for offending polluters, it is all an empty promise. Additionally, without any sanctions, taxes, or any other repercussions, it still puts fossil fuels on the market as they are still arguably the cheapest fuels available. Some such as Hansen (2015) have suggested a carbon fee as a way of incentivizing lower emissions.
Furthermore, as noble as voluntary agreements could be, without any specific financial compensation for poor nations who are disproportionately hit by climate change, there is no climate justice. Additionally, without any legal repercussions for not abiding by the agreement, poorer nations will be hit even harder - which again breaches climate justice. There is no environmental justice - despite what others claim it to be.
Although there are so many aspects of the agreement that I am not completely happy with, we must also acknowledge that the COP21 agreement is definitely a step in the right direction. I only hope that the future COP summits will acknowledge more on the actual causes of anthropogenic climate change (such as our unfortunate reliance on fossil fuels, as well as overuse of nitrogen fertilizer.) I also hope to see more on the technological aspect on how to combat climate change. For example, the lack of mentions of technological advancement in combating climate change such as carbon dioxide removal and solar radiation management. However, I am still hopeful that there is a way for humanity to come together properly without any fossil fuel backing in the future.
The lack of legally binding-ness, is another problem highlighted by many others. It is not mentioned in the agreement at all (or rather, it is phrased as 'partly legally binding and partly voluntary'), and without any consequences for offending polluters, it is all an empty promise. Additionally, without any sanctions, taxes, or any other repercussions, it still puts fossil fuels on the market as they are still arguably the cheapest fuels available. Some such as Hansen (2015) have suggested a carbon fee as a way of incentivizing lower emissions.
Furthermore, as noble as voluntary agreements could be, without any specific financial compensation for poor nations who are disproportionately hit by climate change, there is no climate justice. Additionally, without any legal repercussions for not abiding by the agreement, poorer nations will be hit even harder - which again breaches climate justice. There is no environmental justice - despite what others claim it to be.
Although there are so many aspects of the agreement that I am not completely happy with, we must also acknowledge that the COP21 agreement is definitely a step in the right direction. I only hope that the future COP summits will acknowledge more on the actual causes of anthropogenic climate change (such as our unfortunate reliance on fossil fuels, as well as overuse of nitrogen fertilizer.) I also hope to see more on the technological aspect on how to combat climate change. For example, the lack of mentions of technological advancement in combating climate change such as carbon dioxide removal and solar radiation management. However, I am still hopeful that there is a way for humanity to come together properly without any fossil fuel backing in the future.
Wednesday, 23 November 2016
COP21 my criticisms
As much as I would like to believe COP21 was a successful event, especially given how we got international leaders to cooperate with each other to combat the threat of climate change, I must also emphasize that I was left slightly disappointed with certain aspects of the agreement. This post will explore what I felt was lacking in the agreement.
My first criticism relates to what is referred to as 'differentiated responsibility'. This idea was enforced from the 1992 UN Climate Convention, which implies that different countries have different levels of obligation when it comes to reducing emissions, and financing climate action. This idea is reinforced in the COP21 agreements' article 9. This specific article was one that I talked about in my previous post regarding how developed country parties providing financial resources.
My issue with this article, despite how noble the cause was, the way the agreement places countries into old archaic boxes of development. For example, according to the UN's 2014 document on country classifications, the category of 'developed' countries massively overlook the socioeconomic changes that have occurred in many regions. For example, within the developed economy box, the only mention of an Asian country is Japan. Intriguingly, all other Asian countries which have quickly risen in economic prosperity such as China, Hong Kong, and Republic of Korea, are still under developing countries. My confusion is exacerbated as that same document also lists Hong Kong and the Republic of Korea within the bracket of High Income Economy per capita GINI. These countries are arguably a stronger economy compared to Greece (who is experiencing major economic crisis) - yet they are still considered developing. Article 9 (2) states that developing countries are 'encouraged to provide or continue to provide support'. In that sense, many of these economies despite their strength, won't have to provide climate finance. I understand that there are countries that contribute massively - such as China providing $3.1 billion to the climate fund - but this is not representative of all countries that are within this murky definition.
One aspect of COP21 that shocked me was the lack of attention given to fertilizers, especially given how fertilizers for agriculture account for at least 10% of the global greenhouse emissions. Fertilizer use is not explicitly mentioned within the agreement, apart from slight references to 'safeguarding food security'. Arguably, the only real mention of sustainable food production is in Article 2.1, where it encourages to help 'foster climate re silence ... in a manner that does not threaten food production'. The mention of 'climate-smart agriculture' is fantastic, but personally felt a little weak. The limit of 1.5°C above pre-industrial levels mean very different scenarios for agriculture.
For example, the graph below shows the impact of temperature rise on crops under 1.5°C to 2°C scenarios.
I understand that by limiting the temperature increase to 1.5°C , it limits the yield change impacts on major crops. However, this doesn't mean that there are little difference regionally. For example, maize grown in tropical regions such as in many parts in Africa will be the most impacted regardless of the temperature change. How COP21 will accommodate for these impacts, is another question. Changing the methods of irrigation will help adapt to the new climate scenarios, but this cannot be enough to account for the already food insecure regions. I do not understand how agriculture was not a main part of the COP21 agreement text whilst it was so prominent in countries' intended nationally determined contributions. According to CGIAR Research Program on Climate Change, out of the 160 parties that submitted INDCs, 80% of them have included agriculture in climate change targets, as well as 64% noting agriculture to be central to climate adaptation.
Additionally, I find it odd that fertilizer use was not a big topic considering its centrality to our greenhouse gas emissions. Shcherback et al. 2014's paper found that nitrogen fertilizers were being overused, and exceeding the crop needs. Similarly, Mueller et al. (2014)'s paper investigated the use of fertilizer on cereal production, and its findings indicate that cereal production can be 'achieved with ~50% less nitrogen application and ~60% less excess nitrogen'. From this, I question why fertilizer use was not addressed as much as it should have.
My first criticism relates to what is referred to as 'differentiated responsibility'. This idea was enforced from the 1992 UN Climate Convention, which implies that different countries have different levels of obligation when it comes to reducing emissions, and financing climate action. This idea is reinforced in the COP21 agreements' article 9. This specific article was one that I talked about in my previous post regarding how developed country parties providing financial resources.
My issue with this article, despite how noble the cause was, the way the agreement places countries into old archaic boxes of development. For example, according to the UN's 2014 document on country classifications, the category of 'developed' countries massively overlook the socioeconomic changes that have occurred in many regions. For example, within the developed economy box, the only mention of an Asian country is Japan. Intriguingly, all other Asian countries which have quickly risen in economic prosperity such as China, Hong Kong, and Republic of Korea, are still under developing countries. My confusion is exacerbated as that same document also lists Hong Kong and the Republic of Korea within the bracket of High Income Economy per capita GINI. These countries are arguably a stronger economy compared to Greece (who is experiencing major economic crisis) - yet they are still considered developing. Article 9 (2) states that developing countries are 'encouraged to provide or continue to provide support'. In that sense, many of these economies despite their strength, won't have to provide climate finance. I understand that there are countries that contribute massively - such as China providing $3.1 billion to the climate fund - but this is not representative of all countries that are within this murky definition.
One aspect of COP21 that shocked me was the lack of attention given to fertilizers, especially given how fertilizers for agriculture account for at least 10% of the global greenhouse emissions. Fertilizer use is not explicitly mentioned within the agreement, apart from slight references to 'safeguarding food security'. Arguably, the only real mention of sustainable food production is in Article 2.1, where it encourages to help 'foster climate re silence ... in a manner that does not threaten food production'. The mention of 'climate-smart agriculture' is fantastic, but personally felt a little weak. The limit of 1.5°C above pre-industrial levels mean very different scenarios for agriculture.
For example, the graph below shows the impact of temperature rise on crops under 1.5°C to 2°C scenarios.
Source: Huffington Post |
Additionally, I find it odd that fertilizer use was not a big topic considering its centrality to our greenhouse gas emissions. Shcherback et al. 2014's paper found that nitrogen fertilizers were being overused, and exceeding the crop needs. Similarly, Mueller et al. (2014)'s paper investigated the use of fertilizer on cereal production, and its findings indicate that cereal production can be 'achieved with ~50% less nitrogen application and ~60% less excess nitrogen'. From this, I question why fertilizer use was not addressed as much as it should have.
Saturday, 19 November 2016
COP 21 - My thoughts
December 2015 was one of the most important months of Earth's history. The COP21 summit, held in Paris, was the first legally binding agreement on climate that was signed by 195 countries.
But let's start with the basics. What is COP? Watch the short video below:
However - COP21 should also be praised for a different reason. It had finally put health on the agenda as well, with "the right to health" being central to government action. Although COP21 may have been a 'historic win for human health', Neira and Campbell-Lendrum also emphasize that this is only the beginning.
What sort of implications does COP21 have on health? McMichael et al. (2011) estimated a possible 160,000 deaths and 5 million illnesses each year from the cummulative impact of climate change. With so many affected, health is an agenda that is difficult to ignore.
As we can see from above, greenhouse gas emissions correlate positively with temperature. By cutting net greenhouse gas emissions, it can lead to a cooler planet. Hotter temperatures are linked to increased ozone air pollution. Ozone air pollution has negative impacts on lung functions, which can lead to increased likelihoods of respiratory disorders such as asthma. Whilst 60 ppb of outdoor Ozone is observable in large cities in more economically developed countries - this is the same level that young children with asthma show respiratory symptoms. At the same concentration, young adults had significantly decreased lung function, as well as inflammation of the airways. By decreasing greenhouse gas emissions, we can significantly improve our quality of life.
Additionally, Maria Neria from the WHO has said that 'tackling short-lived climate pollutants ... could result in 2-4 million fewer deaths each year'. In essence, by emphasizing health on the COP21 agreements, it could potentially mean we are getting closer to environmental justice.
What I find interesting is how long it took for health to become a primary aspect when it comes to climate change discussions. For too long has climate change been a topic that felt niche, and the expansion to include health definitely helped to increase the target audience. A paper by Myers et al. 2012 actually found out that framing climate change as a health issue were more effective in 'eliciting emotional reactions'. Furthermore, Maibach et al. also found that using public health to draw attention to climate change was very effective in public engagement.
As happy I was about the outcome of COP21, I do also want to talk about its criticisms - of which I'll explore in my next post.
But let's start with the basics. What is COP? Watch the short video below:
The 'climate bus' has been successful as countries have finally managed to agree on a statement: climate action is essential. An agreement was successfully made. The agreement was to keep temperatures “well below 2C”, have 'efforts' to limit it to 1.5C. The decisions made will mean countries are more responsible for the global climate change, as well as enable governments to seriously look at mitigation and adaptation to climate change. Additionally, COP21 ensured an agreement that countries peak their greenhouse emissions as soon as possible, as well as to strike a 'balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century' which is mentioned in Article 4.
There are many sections within the COP21 agreement. This interactive version of the Paris agreement is really helpful in this.
My favorite part from the whole agreement was Article 9 - which states that economically stronger countries are now committed in climate finance. Additionally, others are encouraged to provide voluntarily. Although the finance, as Evans states, is unspecific, I believe that the legal obligation to contribute to the Green Climate Fund (from COP17) is a stronger decision than before. Currently, more economically developed nations must provide at least USD $100 billion annually from 2020 to help the less developed countries adapt to the pressures of climate change, as well as help the transition to cleaner sources of energy (although ironically, not all developed nations have fully transitioned to clean energy yet.)
Twitter (Source) |
However - COP21 should also be praised for a different reason. It had finally put health on the agenda as well, with "the right to health" being central to government action. Although COP21 may have been a 'historic win for human health', Neira and Campbell-Lendrum also emphasize that this is only the beginning.
What sort of implications does COP21 have on health? McMichael et al. (2011) estimated a possible 160,000 deaths and 5 million illnesses each year from the cummulative impact of climate change. With so many affected, health is an agenda that is difficult to ignore.
(UNFCC 2013) |
Additionally, Maria Neria from the WHO has said that 'tackling short-lived climate pollutants ... could result in 2-4 million fewer deaths each year'. In essence, by emphasizing health on the COP21 agreements, it could potentially mean we are getting closer to environmental justice.
What I find interesting is how long it took for health to become a primary aspect when it comes to climate change discussions. For too long has climate change been a topic that felt niche, and the expansion to include health definitely helped to increase the target audience. A paper by Myers et al. 2012 actually found out that framing climate change as a health issue were more effective in 'eliciting emotional reactions'. Furthermore, Maibach et al. also found that using public health to draw attention to climate change was very effective in public engagement.
As happy I was about the outcome of COP21, I do also want to talk about its criticisms - of which I'll explore in my next post.
Friday, 11 November 2016
Nitrogen cycle Part 3?
Unfortunately, I didn't get to quite finish my last post from yesterday. So this is a continuation of it.
The environmental consequences are not limited to acid rain. Nitrogen released into the atmosphere can combine with water droplets and cause another huge problem in the form of acid rain. Nitric acid rain sources are not limited to fossil fuels, but also linked to fertilizer uses. With nitrogen saturation, nitrogen emissions to streams, groundwater and atmosphere are increased.
Soil quality gets affected by nitrogen saturation. Nitrate discharge from the soil into streams and groundwater means that it also carries minerals such as calcium, magnesium, and potassium. As a consequence, the resulting soil quality is often low due to the loss of essential minerals for future plant growth. The acidification of soil as well as the release of nitrites into streams and groundwater consequently can lead to toxic concentrations of minerals such as aluminum which have devastating impacts on tree roots as well as on aquatic species.
Whilst there are many indirect impacts on human health from nitrogen cycle alterations, there are arguably two main direct impacts:
Atmospheric nitrogen has a huge impact on humans. For example, nitrogen oxides (which are products of fertilizers and fossil fuel combustions) help produce O3, commonly known as ozone. Ozone exposure has negative impacts on human health by inducing respiratory tract inflammations, asthma, and other chronic respiratory diseases. Air pollution, which is typically worse in urban areas, account for at least 2 million deaths annually, which makes this issue quite substantial.
Whilst researching on the health impacts of the Haber process, I stumbled across an illness called methemoglobinemia, or most commonly known as the 'Blue Baby Syndrome'. This illness is related to nitrate uptake by babies from drinking nitrate contaminated water. The nitrate from the water is converted into nitrites by the digestive system, causing a bond with oxyhemoglobin and creating metheglobin - which greatly limits babies' ability to contain oxygen. Because the body is being deprived of oxygen, the baby's body turns a slight shade of blue, and can eventually lead to death.
To end this post, there's one paper by Vitousek et al. (1997) which details all the different human impacts on the global nitrogen cycle that may be worth taking a look into if you are more curious in specificality. To conclude this section of my blog, I am quite saddened by how capitalism (despite its scientifically dynamic nature) has also meant huge consequences that may not be rectifiable. Furthermore, I am increasingly pessimistic on that despite how there is fertilizer available, its impacts are varied globally and that there is a crisis of overproduction juxtaposed with a hunger and malnutrition crisis. Additioanlly, I do wonder why we have not found a way around this yet and how this issue is not widely spoken about - especially when it ends up breaching environmental justice.
In my next post, I hope to explore the UN and its recent COP21 agreement.
Thursday, 10 November 2016
Capitalism and the Nitrogen Cycle
In my previous post, I discussed how the capitalist system has meant changes in the way we utilize the planet. In particular, I explored how the Haber process (a Capitalist invention to maximize food production) has invented industrial agriculture. I also implied that this has also had major impacts on the nitrogen cycle of the Earth. As promised, this post will explore the different consequences of the changes in the nitrogen cycle on the planet, and on us.
To start off, I'll explain what the Nitrogen cycle is.
There are many stages to the nitrogen cycle: nitrogen fixation, nitrification, ammonification, denitrification, and annamox. This is shown in the diagram below.
Although nitrogen may be abundant, they are in the form of gas (N2), however they are inaccessible to plants unless they are converted to ammonia. Nitrogen fixation converts N2 into NH3 (Ammonia) through prokaryotes that break the triple bond present in N2. This process is not limited to prokaryotes, as nitrogen fixation can be done abiotically by lightning, or by industrial processes such as fossil fuel combustion. Nitrification occurs after nitrogen fixation, where it converts ammonia into nitrite then nitrate. Anammox refers to the oxidation of ammonia, and are considered an important process in the global nitrogen cycle for the loss of nitrogen in environments such as oceans.
Denitrification, like the name suggests, indicates the process of converting nitrate to nitrogen gas and eventually releasing it into the atmosphere. There are two reactions involved in this process, and can also lead to nitrous oxide (a greenhouse gas!) being released too. Denitrification can be quite threatening to the agricultural industry as the process removes nitrates from fertilizers which can be a costly consequence. Lastly, ammonification is when nitrogen in tissues of organisms decompose and release ammonia into the ecosystem.
Now that we have covered what the nitrogen cycle is, let us look into the implications of the changes we have made in the nitrogen cycle through activities such as agriculture and energy production. The graph below reinstates the point I made in my last post on how much we have changed the enviroment through anthropogenic activities.
One of the biggest impacts of agriculture (in particular, fertilizers) is the resulting algal bloom and eutrophication. The video below summarizes this pretty well.
To start off, I'll explain what the Nitrogen cycle is.
There are many stages to the nitrogen cycle: nitrogen fixation, nitrification, ammonification, denitrification, and annamox. This is shown in the diagram below.
Source: Nature.com |
Although nitrogen may be abundant, they are in the form of gas (N2), however they are inaccessible to plants unless they are converted to ammonia. Nitrogen fixation converts N2 into NH3 (Ammonia) through prokaryotes that break the triple bond present in N2. This process is not limited to prokaryotes, as nitrogen fixation can be done abiotically by lightning, or by industrial processes such as fossil fuel combustion. Nitrification occurs after nitrogen fixation, where it converts ammonia into nitrite then nitrate. Anammox refers to the oxidation of ammonia, and are considered an important process in the global nitrogen cycle for the loss of nitrogen in environments such as oceans.
Denitrification, like the name suggests, indicates the process of converting nitrate to nitrogen gas and eventually releasing it into the atmosphere. There are two reactions involved in this process, and can also lead to nitrous oxide (a greenhouse gas!) being released too. Denitrification can be quite threatening to the agricultural industry as the process removes nitrates from fertilizers which can be a costly consequence. Lastly, ammonification is when nitrogen in tissues of organisms decompose and release ammonia into the ecosystem.
Now that we have covered what the nitrogen cycle is, let us look into the implications of the changes we have made in the nitrogen cycle through activities such as agriculture and energy production. The graph below reinstates the point I made in my last post on how much we have changed the enviroment through anthropogenic activities.
Source:Vitousek et al. 1997
One of the biggest impacts of agriculture (in particular, fertilizers) is the resulting algal bloom and eutrophication. The video below summarizes this pretty well.
Source: FuseSchool - Global Education
Eutrophication is a serious issue that affects aquatic ecosystems. It refers to the 'enrichment of surface waters with plant nutrients'. Although this process does happen naturally, it is increasingly associated with anthropogenic activities such as fertilizer run-off, which is referred to as 'cultural eutrophication'. As the video mentioned, fertilizers can seep into aquatic ecosystems through variety of means such as surface run-off into streams and eventually lakes, as well as seeping through groundwater and tainting water quality (rendering it undrinkable.) Products of nitrifcation: NH4, NO3 are water soluble, which make it easy for movement through the soil profile to groundwater by leaching.
The table below shows the different sources of cultural eutrophication.
Source: UNEP |
As plants are limited in growth by nitrogen and phosphorus, cultural eutrophication encourages the overproduction of aquatic plants and algae. Consequently, agricultural fertilizers and emissions from fossil fuel combustion release nitrogen pollution into these ecosystems. Conversely, phosphoric pollution from wastewater treatment and detergents also seep into these ecosystems, contributing to cultural eutrophication. Whilst phosphorus pollution has been targeted by environmental management strategies which has reduced algal bloom occurrences, it has also meant that nitrogen pollution is passed onto coastal ecosystems, which further drives eutrophication.
I mentioned earlier that eutrophication can occur naturally, paleoecological investigations into the historical records of eutrophication have shown that they align closely to industrialization, urbanization, and anthropogenic discharge. Similarly, as increased nitrogen emission into the atmosphere is linked to increased deposition of nitrogen on ecosystems, Greenland ice cores have shown an increase in nitrogen isotopes that are linked with industrialization, which was notorious for its use of fossil fuels. Fossil fuels can be seen as nitrogen reserves, and as they are increasingly used, more nitrogen is deposited into the air, and then dissolved into the water which consequently encourages eutrophication.
Increased nitrogen deposition can lead to nitrogen saturation, which negatively impacts soil fertility, which further deter future potential agricultural growth. Additionally, algal blooms lead to reduced dissolved oxygen content in aquatic ecosystems, leading to detrimental impacts on the biological equilibrium which includes fish kills.
Of course, there are more consequences of anthropogenic impacts on the nitrogen cycle. I'll write about this tomorrow, since I'm finding this quite fascinating.
Before I sign off this post, I wanted to discuss something really quickly. The geographies of Nitrogen distribution should also be considered. For example, whilst there are regions such as Sub-Saharan Africa which experiences little direct input from added nitrogen, other regions such as Northern Europe have had major changes. Personally, I find it interesting that different regions are experiencing different extent of impacts. Additionally, in a world where Nitrogen-based fertilizers are so readily available, I find it rather odd that there are countries where malnutrition and hunger is a regular occurrence. Again, this is the result of not only previous colonial history, but also reflective of the capitalist system.
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