I was preparing for Atmospheric Chemistry’s exam when this question popped up in my mind. So, first of all, I hope you all know about our beloved Carbon Cycle. You should also know that carbon dioxide is a major greenhouse gas and recently its concentration in atmosphere has increased to 400ppm mainly due to human activities.
So, now comes the question how carbon cycle acts as a thermostat for our Earth? It does so mainly by positive and negative feedback mechanisms. In positive feedback, the processes that are occurring in nature are enhanced (for example, upon increase in temperature these mechanisms support warming), while in negative feedback mechanisms, the processes are opposed (for example, upon increase in temperature these mechanisms support cooling). Maybe this figure will explain them better than I can!!
Now let’s observe how climate change affects carbon cycle and its feedback mechanisms.
- Terrestrial Environment
In some areas where temperature increases due to climate change, there will be an increase in respiration by plants and this will reduce carbon storage in plants, releasing more carbon dioxide to the atmosphere (positive feedback). Though, in other areas where decrease in temperature occurs, the period of photosynthesis will increase as respiration will be slow, thus carbon will be stored from atmosphere (negative feedback). More carbon dioxide concentrations also support higher rate of photosynthesis.
Similarly, soil stores more carbon at colder temperature and high precipitation as rate of decomposition is reduced.
This table clearly represents how various factors effect feedback mechanisms.
2. Ocean Feedbacks
CO2 is far more soluble in colder water than in warmer water, thus warmer sea surface temperatures will affect the oceans’ ability to dissolve CO2 and their carbon chemistry. A warmer ocean might cause dissolved organic carbon to decompose faster and convert to CO2, reducing the amount of atmospheric CO2 that can be absorbed by the oceans (a positive feedback). Warming might also cause a decrease in the extent of sea ice, which could increase plankton and other marine growth in high-latitude regions. This would result in a greater uptake of atmospheric CO2, thereby acting as a negative feedback (Read more here).
Evidence exists that the relationship between climate change and carbon cycle will be very important in the future for determining emissions and carbon dioxide concentrations in the atmosphere.
This specific issue became evident to me when I surfing twitter. Artisanal and small-scale gold mining (ASGM) is the extraction of minerals by miners working in small and medium sized operations, using rudimentary techniques. Simple practices with minimum economic investment are employed be these miners. It is the largest intentional-release source of mercury in the world.
How can mercury be used for gold-mining? Mercury is used to separate and collect the gold from the rocks. Mercury binds with gold to form an amalgam which facilitates it to separate from rock, sand or other material. The amalgam is then heated to vaporize the mercury leaving the gold behind.
Mercury is a powerful neurotoxin that is harmful to people, especially to developing fetuses, and young children. Once emitted, it can travel great distances through the atmosphere, causing global contamination of ecosystems, fish, birds, mammals, and the human food chain.Local exposures in mining communities that use mercury can be acute.
What to do now?
- The most important measure a mining community can take to reduce its mercury use is to concentrate the gold-containing portion of the ore before adding mercury. This can be done by crushing and grinding the ore and then using carpeted or magnetic sluice boxes or gravity concentration techniques such as panning or centrifuges. In this way, more gold will be captured, less mercury will be required and residual mercury can be more completely captured.
- Protective measures include the use of retorts when burning amalgam and the use of gloves by those handling mercury or amalgam.
- Most promising technology to replace the use of mercury is cyanidation, but this method may not be affordable or technically available to all artisanal miners. Also, cyanidation methods must be used with care and carefully introduced due to its significant risks to human health and the environment.
For further info check reference texts http://www.unep.org/hazardoussubstances/Portals/9/Mercury/AwarenessPack/English/UNEP_Mod3_UK_Web.pdf
(For those who don’t like reading science stuff scroll down and have a look at the infographics)
Agroecology is this short answer. It can help us establish sustainable food systems.
Just a few month back I was very surprised and unhappy that we were to be taught this subject. But since I attended this subject’s first class I have been in love with it. So, the first question in your mind would be what is wrong with our current food system. The following infographic will make that clear to you and later on I’ll ramble about it.
The current agriculture is highly dependent on human inputs. This dependence is mainly due to the agricultural practices like monoculture (planting same crop over a larger area), intensive tillage, use of fertilizers, insecticides, pesticides, factory farming, etc. These practices make an ecosystem of their own that is agroecosystem. Agroecosystem cannot sustain itself. In this system, energy and nutrients are lost. It is not resilient to disturbances and change. It has very simplified food chains. Hence, agroecology applies ecological principles to agroecosystems. This can be done by increasing biodiversity thus making food chains complex, agroecosystems stable, reducing dependence on human inputs, etc. Some of these methods have been beautifully described in the following infographic.
The difference between agroecological and conventional agricultural practices can be observed very clearly in this infographic.
Here goes an infographic about how agroecology relates to climate change.
Sources of infographics have been linked.
I think this infographic summarises it all.
So, in my last post, I asked you for your suggestions at Need Suggestions Please (about shoes)! about whether or not to buy high boots. If you visit my previous post you’ll understand why I wanted suggestions. Thanks to the suggestion of milae, I was motivated to buy them. I ordered them online (my first online shopping experience) and they look awesome.
So, Alhamdulillah I fulfilled my dream!
P.S: Mehwish you’re right. I have bought them but still don’t know how I am going to wear them!
Last quiz’s winner is Mehwish Younus Shaikh. She is an amazing blogger. Do check out her blog!
Please answer this question by typing in the correct option in the comments section.
Does it ever happen to you that you suddenly feel sad and lonely even if you are sitting in the middle of a crowd? You become distant from others? Your mind wanders and all you want to do is to look at something far away? Your voice suddenly lacks any emotions? You speak in a low tone, a lonely tone?
There are some days when I feel like it. Maybe that is why I love this picture so much. Maybe that is why I love autumn and lonely benches. Maybe that is why I want wind to breeze through me. Maybe that it why I love looking at the rain droplets running down my glass window.
But then I think. I look around me. Observe my life. Look at all the beautiful things God has blessed me with. Look at family, my uncles, my aunts, my friends. Look at those who love me, care about me, and can sacrifice everything for me. And suddenly realize that I have no legitimate reason to be unhappy. I shouldn’t be unhappy. I should be thankful to Allah for giving me whatever is best for me.