Forest Future

Credit: Alice Fitch. South Cardamoms

We left our ancestors in the last post just getting involved in agriculture - but let's fast forward to today. One of the major side effects of agricultural expansion is deforestation (Chaplin-Kramer et al., 2014). The global impacts of this deforestation relate to:

• Carbon Storage
• Loss of biodiversity
• Hydrological changes
• Habitat fragmentation

In today's world with all our intensification methods, we could question is agricultural expansion still occurring, namely, will we see more deforestation for agriculture?

This is where modelling can help us; Schmitz et al., (2006) compared the results of 10 agro-economic models —MAgPIE, GLOBIOM, GCAM, IMPACT, AIM, FARM, GTEM, ENVISAGE, MAGNET, EPPA — under a number of scenarios considering socioeconomic developments and climate change to assess how much land will be used for crops in 2050. Modelling inter-comparison is really important for attempting to 'predict' the future as each model reaches its conclusion in a different way; this happens as models differ in the number of land-use types they employ, what assumptions they apply, and what they consider the most important for determining crop allocation and expansion (Schmitz et al., 2006). Additionally, scenario modelling allowed us to handle uncertainty in changing climatic and economic conditions.  

Their findings: a global rise in the amount of land devoted to agriculture — possibly 200-300 million more hectares— with the greatest regional increases in sub-Saharan Africa and South America, and a general decrease in Europe (Schmitz et al., 2006).

Figure 1. The graph shows the development of cropland from 2005 to 2050, all data is normalized to HYDE model data for 2005. The boxplot shows the change in cropland under S1: no climate change, medium economic growth and population development. S2: no climate change, lower population growth in developed countries, higher in developing countries. S4 and S6: medium economic growth and population development with pessimistic climate change scenarios (Schmitz et al., 2006). 

 As we can see in figure 1, the underlying modelling processes meant models did differed in their results: FARM for instance predicts a global decrease, while IMPACT and GCAM show increases and decreases across the 50 years. 

However, it is important not to rely too much on the results as these land use models are all relying on data from the other models the authors used to model climate, hydrology, vegetation, crop growth, population growth etc. These models in themselves hold their own assumptions and difficulties, for instance with vegetation you have to take into account phenology, water requirements, amount of photosynthetic radiation, CO₂, nutrient limitation etc. to be able to model growth. Scale this up globally and you can see where errors could creep in! 

BUT, after we have taken all this into account, what is interesting with the study is that across the extreme scenarios there is a trend towards global increases in cropland by some degree. SO I think we will see more agricultural expansion globally, occurring more in developing countries due to socioeconomic factors, and therefore more deforestation occurring as a result of land use change.

So, what will this do for our environment?

Let's find out in the next post! Forests of Carbon or Fields of Food......

The Rise of Agriculture

Agriculture [noun]: the science or practice of farming, including cultivation of the soil for the growing of crops and the rearing of animals to provide food, wool, and other products.

                                                                                                        (Oxford University Press 2015)

The main themes of my blog that I will use to explore to the effects of feeding us is how agriculture causes global environmental change through: 

                - the conversion of land 

                - the production methods used

First I thought to find out how agriculture started...

As we are delving back into time, key geological epochs to know about are the Pleistocene — which began roughly 2.58 million years ago (Gibbard and Head 2010) to roughly 11,700 years ago (Walker et al., 2009)  — and the Holocene which directly followed it. When exactly the Holocene finished (and the Anthropocene which we are in now began) is one of much debate, some interesting articles on the subject are available here and here. But for us the end of the Pleistocene and beginning of the Holocene are the most importance for agricultural origins.

From hunter-gatherers to agriculturists

Why we moved from hunter-gatherers to an agricultural society is intriguing, it is thought to be due to climatic change at the end of the Pleistocene. Through studying ice cores we can see the climate of the Pleistocene went through periods of abrupt warming and cooling (Cummings et al., 2006), and this unreliable climate is thought to have made agriculture pretty much impossible for our ancestors (Richardson et al., 2001). As the last ice age of the Pleistocene came to an end the earth entered a new epoch, the Holocene, which had a much warmer and more stable yearly climate. We can see this change in the ice cores as demonstrate in figure 1. below:

Figure 1: Graph showing isotope levels of oxygen from ice-cores, which reflect temperature changes. (Cummings et al., 2006)   

This new climate allowed agriculture to be a feasible long term option (Richardson et al., 2001), and using radiocarbon dating we can see that agriculture appeared during this time. Adapting to this changing climate, agriculture seems to have developed separately in about 9 locations (Diamond and Bellwood 2003) and then spread globally as, compared to hunting and gathering, agriculture could support larger populations. (Richardson et al., 2001, Diamond and Bellwood 2003):

Figure 2. Archeological map of agriculture homelands and spread of associated cultures, with approximate radiocarbon dates  (Diamond and Bellwood 2003). 

Exactly how those hunter-gatherers began agriculture appears to have been a fairly gradual process incorporating a combination social and technological factors (Cummings et al., 2006). Many groups already had an agricultural element to their societies from which they expanded upon and Roth (2006) provides interesting evidence for women driving the adoption of agriculture, and how it began as an extension of their 'gathering' role (girl power eh!). 

So that's how we became an agrarian society. I hope you found out something new and i''ll leave you here with this interesting tidbit:

Though agriculture dominates the globe hunter-gatherer societies still remain out there, one such example is the Sentinelese people living on North Sentinel Island in the Bay of Bengal. They are one of the last ‘un-contacted' tribes and have been able to remain this way for so long due to being incredibly hostile to any outsider contact. If you are interested in learning more about them click here.

Credit: North Sentinel Island 2015

Till next time!

Welcome!

If you are like me then you love food, one of my favourite programs has to be The Great British Bake-Off (though my attempts never turn out so good) and I try to grow veg in my garden. But (other than my garden) where does our food come from?

I know I can hear the exasperated sighs and the words of a student I used to teach: "errrr.... from the ground miss!" but in today's society we go to the supermarket to forage; purchasing any vegetable/fruit/nut/meat whatever the season. Yes we know what country our food comes from and whether it is organic and free range, but beyond this how much do we know about its production, specifically: how big is the impact of feeding 7.3 billion people (Worldometers.info 2015)?




Source: The Department Store

This is the wider question that I hope to explore over the next 3 months with my blog 'Perpetually Hungry': where I will use environmental models to look at the impact of agricultural land-use on our environment and question how sustainable it is to continue such methods.

So tune in as I hope to provide you with a thought-provoking read as well as some interesting knowledge that can be stored for those intelligent dinner-party/first-date/meet-the-parents/on-the-train-with-my-lecturer-lets-not-babble-like-an-idiot conversations (maybe the last one is just me). Please comment on posts as I would love to know your thoughts on the issues I cover.

This concludes my introductory post, and so I will leave you with a quote by Tomkin (2002) to ponder on: "Environmentalism begins at the breakfast table."

Till next time!