The Elephant in the Forest: Population Increase and its Effect on Deforestation

Introduction

The principal cause of the increase in greenhouse gases (GHG) is the burning and/or use of fossil fuels. These add about 9.3 billion t of carbon (34.2 billion tCO2) to the atmosphere each year, but land use changes also contribute another 1.4 billion t. C the GHG total [1].

There was little if any talk at the 2017 Bonn meeting on global warming [2] nor at the December 2018 meeting in Katowice (Poland) [3] about one of the causes of the increase in atmospheric carbon dioxide (CO2), namely deforestation. While the Polish President declared a ‘forests for climate policy’, highlighting the important role of forests in solving the climate problem, a resolution welcoming the IPCC 1.5oC report was objected to by four countries, namely USA, Saudi Arabia, Russia and Kuwait, who wanted the report only to be ‘noted’ not ‘welcomed’. Thus, this resolution was postponed to the next Subsidiary Body for Scientific and Technological Advice (SBSTA) to be held in Bonn in June 2019 [4]. According to the latest (December 2018) Climate Action Tracker [5], the increase in temperature is already 1°C above pre- industrial levels and current national policies will result in a 3.3°C warming by 2100 (range 2.5 to 4.4°C). Even the optimistic scenario forecasts 3.0°C warming by 2100

(range 2.4 to 3.2°C). http//climateactiontracker.org. Therefore, there is much to be done to promote the ‘Sustainable Development Goals’ (SDG) and promoting vigorous reforestation and timber use and population control must be given high priority.

The latest Food and Agricultural Organization’s State of the World’s Forests [6] and Global Forest Resource Assessment [7], estimate that about 1.4 billion (109) tonnes of carbon (5.1x109 tCO2) (range 1.1 to 1.6 109 tC) are added each year to the atmosphere through deforestation. This is likely to continue due to population pressure and increase in wealth: this could increase, unless steps are taken to decrease deforestation, especially in tropical countries. The principal causes of deforestation are population increase (for subsistence agriculture) and the increased demand for arable and pastoral land for commercial crops such as soy beans, palm oil, coffee and cattle feed [8]: this is what I term ‘the elephant in the forest’.

As people and countries increase their wealth, the rate of population increase declines; this is especially true for China and to a lesser extent India – the two most populous countries. However, in many developing countries and regions, because of the bulk of the population is or will be in the reproductive stage of life, the rate of increase only declines slightly. Thus, the population of in Sub-Saharan Africa (SSA) is forecast to increase by over 300% between 2015 and 2100 if little is done to temper this increase. This may have a profound effect on the rate of deforestation in SSA. Also, in LDCs excluding China, the population may nearly double between 2015 and 2100! How will this affect deforestation?

Urbanization and infrastructure development also contribute somewhat to land use change, but very little from the use of forest resources: the latter may cause some forest degradation, but rarely deforestation: this only occurs when there is a land use change, for ‘nature abhors a vacuum’. Population statistics: In 2015, the population of the world was estimated to be 7,349 million and by mid-2019 is due to reach 7,678 million. It is forecast to grow to 9,725 million by 2050 and to over 11 billion by 2100 [9]. Table 1 gives the population protections for specific years for the world and selected regions, plus the total for less developed countries (LDC). The LDC total is less than the sum for Africa, Asia and Latin America and the Caribbean to account for countries not considered to be LDCs.

Table 1: Population Projections for the World and Regions. Units million. Note. Sub-S Africa = Sub Saharan Africa (SSA). L.A.&C = Latin America and the Caribbean. LDC = Less developed countries. The total for LDCs is slightly less than the sum for Africa, Asia and L.A.&C to account for countries not considered as LDCs. % incr. = percentage increase in population from 2015 to 2100. excl. = excluding. Source. Population Pyramid 2018 [9].

Deforestation Effect of Population Increase

According to FAO statistics [6, 7], for the period 2010- 2015, the deforestation rate was 7.6 million ha per year, of which natural forests declined by an estimated 6.5 million ha/yr. The bulk of the decline was in tropical areas namely SSA (3.1 million ha/yr.), LA&C (2.2 million ha/yr.) and Asia excluding China (1.0 million ha/yr.). The decline in other areas was 0.2 million ha/yr. Of course, there were gains in forest areas - an estimated 3.48 million ha/yr., notably in China (+1.54 million ha/yr.) - but it will take many years for these gains to offset the carbon loss from the cleared natural forests and woodlands.

In SSA, two-thirds of forest loss was due to subsistence agriculture, whereas in LA&C, 70% of the loss was due to commercial agribusiness - clearing land for soy bean, palm oil and cattle ranching etc. Between 2015 and 2100, the loss of natural forest and woodland could range from 500 to 800 million ha (5.9 to 9.4 million ha per year), of which an estimated 350 to 520 million ha will be due to the subsistence sector. An estimated 66% of the loss will be in SSA, 30% in Asia and 4% in LA&C1 [1]. If these estimates are anything near the truth, then the annual emissions of CO2 from deforestation will be in the region of 3.2 – 5.2 billion tonnes adding to GHG! This will profoundly influence global warming and negatively affect the goal of keeping the global temperature increase below 20C from pre-industrial levels – as per the Paris Climate Accord, ratified in November 2016 and action taken at the UN Convention on Climate Change [2]. The aspirational goal from COP24 is keeping the increase in temperature to 1.50C above the pre-industrial level [3]. But, according to the latest results from the Carbon Action Tracker [5], most countries are nowhere even near the 20C target, let alone the 1.50C aspirational figure. Clearly there have to be concerted efforts from scientists, concerned industrialists, the private sector, non- government organizations (NGOs), councils and individual people, especially young people, to put considerable pressure on governments and international bodies to take realistic and immediate action on the proposals from COP 23 & 24. Otherwise, humanity may be in serious jeopardy.

Necessary and Urgent Steps to Meet the Climate Goals

What steps are necessary to reverse this trend and could trees help to meet the goals of the Paris Climate Accord by helping reduce GHGs? Governments have to be much more serious in promoting the sustainable development goals (SDG) and reducing fossil fuel use: this could be done through (increased) carbon taxation, reducing or elimination subsidies on fossil fuels, promoting renewable energy, improving end use efficiency, etc. All these measures have been discussed in detail in COP 23 & 24 etc. and will not be described further here. What will be elaborated is ways to promote carbon sequestration through biomass and to reduce, if not reverse, deforestation. The solutions are several -

1 These are ball park estimates based on some increase in agricultural productivity and the rate of urbanization in LDC’s. Many LDCs will be importing food, especially to feed the urban population. However, the quantity of suitable forest and woodland will decline, and more and more less productive forest cover will be converted to temporary or permanent crop land and pasture. The ‘shifting cultivation’ cycle under crops will decrease, causing an increase clearing of forest etc. Thus, the above estimates may be low.

such as increasing agricultural and silvicultural productivity, reclaiming abandoned and/or degraded lands, stabilizing shifting cultivation, protecting water sources, vesting forest resources in people at the local level and paying them for protection, improving intermediate and end-use efficiencies of wood products, decreasing (food) waste, altering eating habits away from animal proteins, improving infrastructure and education and tempering population increase, especially through empowering women.

Increasing Agricultural Productivity

While at COP 24, the Polish President declared ‘a Forest for Climate Policy’ promoting tree planting and management, but of equal importance should have been ‘a Farm for Climate Policy’ especially geared to the subsistence sector in LDCs. The main causes of deforestation are clearing land for subsistence agriculture, including shifting cultivation, due to population pressure and the increased demand for cash crops, not harvesting wood as is often cited [10]. Can this clearing be slowed down and eventually reversed? Can agricultural productivity increase by at least the rate of population increase?

The usual methods to increase agricultural productivity are: applying increased amounts of artificial fertilizers, which are produced using fossil fuels; crop and animal breeding, including genetically modified crops; applying pesticides and herbicides; plastic sheets over salad and soft fruit crops and hydroponics etc. It is said that such measures will supply enough food to satisfy the increased demand brought about by population increase and increased wealth [11].

Another intervention is planting shelterbelts to reduce evapo-transpiration of cash crops to increase yields. These are promoted in several countries from China to Egypt. However, there are additional effective ways to increase productivity using ‘natural’ methods more suited to subsistence farmers. These include: zero tilling, applying slurry from (cheap) biogas plants, manure management and adding lime to the soil. Again, intercropping with nitrogen-fixing species (including trees) can at least stabilize agricultural productivity, if not improve it: this is commonly known as agro-forestry [12]. Pasture land could be planted with nitrogen-fixing tree species to provide fodder and shelter for animals. There are many existing nitrogen fixing trees (e.g. Acacia sp.) on such lands and increasing their presence should be encouraged.

Nitrogen-fixing tree species can be used to intercrop in place of shifting cultivation and to eliminate the invasive grass species Imperata cylindrical [13]. Brassicas (cabbage etc.) and beans planted side by side can deter the black bean aphid (Aphis fabae) from attacking the cabbage. Another intervention was applied to maize in East Africa. Scientists from Rothamstead agricultural research facility (U.K.) found that planting napier grass (Pennisetum purpureum) round the edges of maize fields and intercropping the maize with molasses grass (Melinis minutiflora), deterred stem borer moths (Busseola fusca and Cholo partellus). These grasses also attracted parasitic wasps that prey on the moths. Not only were maize (and sorghum) yields increase, but the two grasses are edible fodder for cattle, which meant that farmers could increase their animal stock and provide more milk and dung to fertilise the fields [14]. The grasses also increase the amount of carbon stored in their roots and the soil. Again, one of the curses of poor farmers on poor land in Africa (and elsewhere) is witchweed (Striga asiatica) [15], which parasitizes the roots of cereal crops and kills them. The striga seeds can lay dormant for many years and are difficult to control. The same scientists found that a tree legume known as silverleaf (Desmodium uncinatum), if intercropped with maize, resulted in no striga invasion although adjacent maize fields without silverleaf were nearly devastated by it. This more than doubled the yield of maize and the silverleaf provides cattle fodder and stick wood [14]. These are but some examples of the symbiotic relationship between plants that can be easily adapted by farmers, especially subsistence ones, to increase their plant and animal yields.

One of the problems of global warming is that increased temperatures, especially at night, may inhibit the flowers of cereal crops from setting. Rice is the chief crop in many parts of the world, especially in Asia. Scientists at the International Rice Research Institute (IRRI) in the Philippines have a breeding programme to develop rice strains that can tolerate increased night-time temperatures without affecting rice yields, (personal visit). This is but one example of a necessary response to the negative effects of global warming.

Shifting cultivation is a method whereby farmers can grow crops for two or three years on cleared forest areas, before the crop yields are too low for sustenance. The farmers then move to new forest areas and repeat the process, allowing former cleared lands to recover for about 20 years before the cycle is repeated. However, because of increase population pressures, the recovery cycle in many cases is shortened and the cropping time is also curtailed, resulting in lower sustained crop yields and shorter recovery time. Inter-planting nitrogen-fixing crops, especially tree species, can stabilize agricultural productivity and provide animal browse and/or mulch to the soil, as well as stick wood. Also, wood ash is a good fertilizer, being relatively rich in K (potassium), a critical ingredient to maintain soil fertility along with N (nitrogen) and P (phosphorous). Again, applying lime (CaOH) to acid soils improves the availability of P to plants.

Thus nitrogen-fixing plants, especially trees, can stabilise if not increase crop production and increase the carbon store in wood and soils [16]. A book that should be made available to all agricultural and forestry departments in the tropics is Tropical Legumes: Resources for the Future, published by US National Academy of Sciences [17].

Photochemists and photobiologists are actively searching for systems which will split water using solar energy. The advantage of these artificial systems over natural photosynthesis is that they might be optimised for natural photosynthetic efficiency [18]. Another intervention that scientists are working on is making cash crops such as maize and rice fix nitrogen. Hopefully such interventions will be commercial in the not too distant future.

Increasing Silviculture Productivity

Besides increasing agricultural productivity at a rate hopefully similar to that of population increase, it is important to increase the productivity of trees, especially nitrogen-fixing species, through breeding, cloning and selecting species that will stand climate change. Such ‘superior’ species can and should be used to improve carbon storage to help counter CO2 emissions from fossil fuels.

There are considerable areas of farmland, both rainfed and irrigated, that have been abandoned due to land exhaustion, falling yields, salination and invasion by weeds, pest and diseases such as witchweed (Striga asiatica), congon grass (Imperata cylindrica), black bean aphids, stem borer moth etc [15]. Top priority should be given to the reclamation of such abandoned areas and to reducing pests and diseases. These areas are candidates for tree plantations and agro-forestry, but some reclamation costs may be high. Generally, however, tree plantations are a cheaper alternative for ‘Carbon Capture and Storage’ (CCS), than CCS from CO2 emissions from electric power plants with storage underground or under the sea. What is more, the annual yield from such plantations may be used for wood products including fuelwood in place of fossil fuels, thus reducing the demand for fossil fuels and the increased CO2 emissions from them! From 2016 to 2050 about 420 109 tC will be added to the atmosphere from the burning of fossil fuels [19]. Ten percent of this, namely 42 109 tC could be captured say by 2050 in trees and forest soils (CCS). The area of land required for such an intervention, assuming 67% is in the tropics and 33% in temperate areas, would be between 109 million ha (optimistic assumption) at a cost of about $272 billion ($1.7 per tCO2) and 330 million ha (pessimistic assumption) at a cost of $1,243 billion, ($7.7 per tCO2). If the land had to be paid for, then this would increase the CCS price by between $5 and $16 per tCO2. These costs should be compared to the CCS from a power plant, which would cost in the region of $70 per tCO2 [20]. In addition, there is the bonus of the annual yield from such plantations, which ranges from 22t/ha of above-ground wood in tropical areas to 11t/ha in temperate areas. (Openshaw 2015)2 [21].

There are many tree species that can be used to reclaim land, from low to high rainfall areas and from saline to calciferous soils. The US National Academy of Sciences [17] lists tree and other legumes that can be used to restore lands from deserts to tropical highlands. For example, Prosopis spp., including mesquite, can be used to reclaim dry areas, but the total carbon accumulation may only be in the range of 3 to 5 tC/ha/yr. Mesquite is sometimes regarded as a weed species, because animals, especially ruminants, eat the leaves and the seed pods. However, they cannot digest the seed, which is then passed out with the dung. This generally regenerates and spreads. But if the seed pods are collected and milled, thus destroying the seed, the resulting product can be (and is) sold as an excellent animal feed. All legumes, especially tropical tree legumes, have a critical role to play in land reclamation and improving agricultural productivity. Other useful NAS books are: Firewood Crops [22] and Firewood Crops, Volume 2 [23].

A recent intervention to increase the yield of tree species is applying a sustainable fertilizer called Argrow based on a nitrogen-rich amino acid arginine, which is rapidly absorbed by plants [24]. The same newsletter

2This article was published in the African Journal of Food Science and Technology in September 2015. However, I the author made a calculation error and I overestimated the capture of carbon by a factor of 10. The CCS should have been 42 GtC not 420 GtC. I have adjusted the figures to account for this. Even so, CCS with wood is far cheaper than CCS from power plants.

mentions the use of ‘seedpads’ to improve the germination of pine (Pinus sp.) and spruce (Picea sp.) seeds as well as an award given to Dr. Chris Harwood for his work advancing the understanding of breeding Eucalyptus sp., Acacia sp. and Grevillea robusta. – southern oak [24].

Job opportunities

In future, robots and artificial intelligence may deny many people job opportunities, especially in urban areas. Thus, people may be forced back to the land. But in rural areas, job opportunities, especially for women could be expanded. The above carbon, capture and sequestration (CCS) proposal is an excellent way to expand employment opportunities. Rural people, especially women could start tree nurseries, plant and manage trees, protect forests, have stove-building enterprises, and expand the collection, manufacture and sale of wood and non-timber forest products. Plots should be established to demonstrate agro-forestry methods and free seeds, especially of appropriate nitrogen-fixing species, should be made available. All rural schools should have tree nurseries and children should be taught environmental awareness etc. Again, much more effort and money must be provided to promote family planning as in Botswana, China and Thailand. Such ‘population’ and ‘agricultural’ initiatives may require an amount of money equal to or more than the above proposed budget for CCS, but without these programmes, the slowing down of deforestation, even with such programmes as REDD+, may be fighting a losing battle. Those in authority should trust the (rural) people and take them into their confidence. Bureaucracy must be reduced to a minimum. Plantation areas can be checked by satellite, with some ground truthing. It is proposed that rural people willing to plant and manage trees, especially in the tropics, should be paid an appropriate amount of money on a per-ha basis and once the carbon is (fully) captured in the wood and forest soils additional amounts of money could be paid from say the ‘green carbon fund’. Money for planting and management should be handed directly to the people or through trusted chiefs and NGOs etc. This should assist many people, especially the rural poor in developing nations, and be an essential part in the quest for reversing forest loss, GHG mitigation, environmental protection and increased forest and agro-forest areas: this should and could lead to truly sustainable development.