The theme of this year’s Earth Day is “Planet vs. Plastics” – a theme chosen to raise awareness of the damage done by plastic to humans, animals and the planet and to promote policies aiming to reduce global plastic production by 60 percent by 2040.
As our chart shows, global plastics use has increased rapidly over the past few decades, growing 250 percent since 1990 to reach 460 million tonnes in 2019, according to the OECD’s Global Plastics Outlook, which projects another 67-percent increase in global plastics use by 2040 and for the world’s annual plastic use to exceed one billion tonnes by 2052. As our chart shows, packaging is the largest driver of global plastics use, which is why a rapid phasing out of all single use plastics by 2030 is one of the policy measures proposed under EARTHDAY.ORG’s 60X40 framework.
Other major applications of plastics include building and construction, transportation as well as textiles, with the fast fashion industry particularly guilty of adding to the world’s plastic footprint. “The fast fashion industry annually produces over 100 billion garments,” the Earth Day organizers write. “Overproduction and overconsumption have transformed the industry, leading to the disposability of fashion. People now buy 60 percent more clothing than 15 years ago, but each item is kept for only half as long.” Most importantly, the organization points out that 85 percent of disposed garments end up in landfills or incinerators, while just 1 percent are being recycled.
Felix Richter is a Data Journalist
This article was first published in the Statista.com.
The southern African region is battling with drought at present. This is the result of El Niño, a natural climate cycle characterised by changes in Pacific Ocean temperatures. It has effects on global weather patterns, particularly rainfall and temperature.
The drought has hit the region’s agricultural productivity hard. Malawi, Zambia and Zimbabwe have declared a state of disaster with respect to their current agricultural outputs. They are seeking humanitarian assistance in the form of food aid to feed their people. The downturn also has economic implications, since over 70% of people residing in the region’s rural areas rely on agriculture for their livelihoods.
The dire situation underscores how important it is for the agricultural sector to prevent, avoid or prepare for the impacts of climate change, which will also bring extremes of weather.
One measure the sector can take is to cultivate biofuel crops. These are crops rich in starch, sugar or oils that can be converted into bioethanol directly or through a fermentation process. Bioethanol, a type of ethanol produced from biological or plant based sources, emits fewer greenhouse gases compared to fossil fuels like petroleum, natural gas and coal. Commonly used biofuel crops include sugarcane, maize, grain sorghum, sugar beet, rapeseeds and sunflower.
These conventional biofuel crops do have drawbacks, however. They are highly susceptible to extreme weather events. They require high upfront investment for fertilisers, chemicals and irrigation. And they compete with food production – if they’re grown as biofuels they can’t also be used as food because of how they have to be processed.
So, researchers are always on the lookout for crops that might be good biofuels without those problems. Sweet sorghum, which is indigenous to the African continent, is one such crop. Unlike the better-known sorghum, it has sweet juice in its stems. In a recent study, I reviewed scientific literature to analyse the potential significance of sweet sorghum to African farmers because of its multipurpose nature and ability to adapt under harsh climatic conditions.
Multiple uses
Sweet sorghum has many uses. It can produce grains, animal feed and sugary juice, making it unique among crops. The grains from sweet sorghum are prepared as steamed bread or porridge malt for traditional beer, as well as in commercial beer production across the continent.
They’re nutritionally rich, with high energy values (342 calories/100 g), proteins (10g/100 grains), carbohydrates (72.7g/100 grains), and fibre (2.2g/100 grains) as well as essential minerals such as potassium (44mg/100 grains), calcium (22mg/100 grains), sodium (8mg/100 grains) and iron (3.8mg/100 grains).
The nutritional value of maize is fairly similar: proteins (8.84g/100 grains), carbohydrates (71.88g/100 grains), fibre (2.1g/100 grains), potassium (286mg/100 grains), calcium (10mg/100 grains), sodium (15.9mg/100 grains) and iron (2.3mg/100 grains).
What sets sweet sorghum apart from a crop like maize is that it’s also resilient in arid climates and has multiple other uses. For instance, it produces a lot of plant material (biomass) as it grows, which is left over after harvest. That’s why it’s useful as animal feed too.
Animal feed is made from what remains once the sweet sorghum crop has been harvested and its grains and stem juice stripped off. The residue is high in nutritional content, which can improve the quality of diets of animals, including cattle. The grains can also be used for animal feed.
The sweet juice in the crop’s stalks is what’s used to create bioethanol. Sweet sorghum contains sucrose, glucose and fructose, which are essential for bioethanol production. Of the conventional biofuel crops I’ve mentioned, only sugarcane yields more ethanol. Studies in the United States have shown that sweet sorghum far outstrips maize when it comes to bioethanol production: it yields 8,102 litres per hectare planted, while maize yields just 4,209 litres per hectare.
Resilient
Perhaps most importantly given the southern African region’s current drought struggles, sweet sorghum is well-suited for cultivation in the sorts of adverse conditions that are typically challenging for conventional biofuel crops.
One of the key characteristics of sweet sorghum varieties is their drought resistance. It allows them to enter a dormant state during extended periods of dryness and resume growth afterwards. Research has shown that, under intense water scarcity conditions, sweet sorghum makes use of its stalk juice to supplement its plant needs.
Sweet sorghum’s ability to withstand low water and nitrogen inputs, as well as its tolerance for salinity and drought stress, makes it an ideal crop for farmers in arid regions. This is why it’s widely used in other parts of the world, including the US, Brazil and China.
Investing in sweet sorghum
The continent’s current agriculture value chain is dominated by major crops like maize, wheat and rice, which all originate from outside Africa. Not enough attention is given to crops of African origin, like sweet sorghum, even though it is a multipurpose, hardy crop with great potential for farmers. People are more familiar with sorghum, not the sweet variety, and it is also under-researched.
Governments should be using their agriculture extension services to raise awareness among farmers and consumers about the benefits and practical applications of sweet sorghum in people’s diets.
Developing recipes and secondary or industrial products can enhance the feasibility and awareness of sweet sorghum farming. By investing in research and development, the full potential of sweet sorghum cultivation can be unlocked through governments and the private sector.
Hamond Motsi is a PhD Student in Agriscience, Stellenbosch University
Chinese investors have flocked to Zimbabwe to secure lithium supplies, promising local development. But analysts warn Zimbabwe needs more robust governance for communities to reap the benefits. Reports Andrew Mambondiyani
Wonder Mushove stared blankly at plumes of red dust billowing into the sky as more than 30 trucks carrying loads of lithium ore rumbled past his newly-built house in Buhera, in eastern Zimbabwe.
The trucks drive by Mukwasi village on the dirt road linking the Chinese-owned Sabi Star lithium mine to the tarred highway. They travel through the border town of Mutare to the port of Beira in neighbouring Mozambique. From there, the lithium-containing minerals are loaded onto ships and exported to China – the world’s largest manufacturer of lithium-ion batteries.
The dust hung in the air after the trucks’ passage. Mushove and his family were among dozens of households displaced by the $130million-mining project, which began operating in May. They were relocated to new houses built by the mining company about a kilometre from their old homes.
And yet, Mushove is hopeful the mine could “uplift the area and put it on the world map,” he told Climate Home News. For decades, the vast, hard-rock lithium deposits buried under his home were of little interest to foreign investors. Now, Chinese companies are paying a high price to access Zimbabwe’s reserves – the largest in Africa and among the largest in the world.
A lightweight metal with the ability to store lots of energy, lithium is critical for the manufacture of batteries for electric cars. Global efforts to move away from combustion-engine vehicles have pushed demand for the silvery metal, also known as “white gold”, to soar.
Chinese companies have flocked to Zimbabwe’s untapped reserves of high-grade lithium to shore up the country’s supplies, benefiting from the Southern African nation’s cheap labour and deregulated mining sector. In the past two years, Chinese companies invested over $1.4 billion acquiring lithium projects in Zimbabwe.
And more money is on its way. Last year, Chinese companies were awarded licenses that could see $2.79 billion in investment flow into the country, mostly in the mining and energy sectors. These investments could turn Zimbabwe into a key player in the global lithium-ion battery supply chain. Chinese battery manufacturing giant BYD could source some of its lithium from Zimbabwe, after buying a stake in the Chinese owners of the Sabi Star mine.
But Zimbabwe’s poor progress on establishing robust resource governance threatens to keep communities like Mushove’s from seeing any of the benefits, analysts told Climate Home.
A recent investigation by NGO Global Witness in Zimbabwe, Namibia, and the Democratic Republic of Congo found that there is a danger of history repeating itself with lithium mining without rigorous screening for corruption and social and environmental harms.
Isolated by the West and slapped with 20 years of sanctions because of human rights violations, Zimbabwe has turned towards China, now the country’s largest foreign investor.
Since the 1950s, China’s foreign policy has been guided by “five principles of peaceful co-existence“, including a commitment not to interfere in another country’s internal affairs. This principle, which encapsulates China’s approach, has set it apart from western investors.
Zimbabwe’s “opacity and disregard for human rights has made it cheap for the Chinese to exploit minerals” in the country, said James Mupfumi, director of the Centre for Research and Development, a local NGO advocating for accountability in the natural resource sector.
Zimbabwean law vests all mineral rights to the president. With no requirements to disclose the beneficial owners of mining projects, “there is no due diligence and parliamentary oversight on Chinese investments,” Mupfumi explained.
“Above all, Zimbabwe requires a government that prioritises public accountability of mineral wealth, not the self-enrichment of a few political elites,” he added.
The ministry of mines did not respond to a request for comment.
Algeria’s Tassili N’Ajjer plateau is Africa’s largest national park. Among its vast sandstone formations is perhaps the world’s largest art museum. Over 15,000 etchings and paintings are exhibited there, some as much as 11,000 years old according to scientific dating techniques, representing a unique ethnological and climatological record of the region.
Curiously, however, these images do not depict the arid, barren landscape that is present in the Tassili N’Ajjer today. Instead, they portray a vibrant savannah inhabited by elephants, giraffes, rhinos and hippos. This rock art is an important record of the past environmental conditions that prevailed in the Sahara, the world’s largest hot desert.
These images depict a period approximately 6,000-11,000 years ago called the Green Sahara or North African Humid Period. There is widespread climatological evidence that during this period the Sahara supported wooded savannah ecosystems and numerous rivers and lakes in what are now Libya, Niger, Chad and Mali.
This greening of the Sahara didn’t happen once. Using marine and lake sediments, scientists have identified over 230 of these greenings occurring about every 21,000 years over the past eight million years. These greening events provided vegetated corridors which influenced species’ distribution and evolution, including the out-of-Africa migrations of ancient humans.
These dramatic greenings would have required a large-scale reorganisation of the atmospheric system to bring rains to this hyper arid region. But most climate models haven’t been able to simulate how dramatic these events were.
As a team of climate modellers and anthropologists, we have overcome this obstacle. We developed a climate model that more accurately simulates atmospheric circulation over the Sahara and the impacts of vegetation on rainfall.
We identified why north Africa greened approximately every 21,000 years over the past eight million years. It was caused by changes in the Earth’s orbital precession – the slight wobbling of the planet while rotating. This moves the Northern Hemisphere closer to the sun during the summer months.
This caused warmer summers in the Northern Hemisphere, and warmer air is able to hold more moisture. This intensified the strength of the West African Monsoon system and shifted the African rainbelt northwards. This increased Saharan rainfall, resulting in the spread of savannah and wooded grassland across the desert from the tropics to the Mediterranean, providing a vast habitat for plants and animals.
Our results demonstrate the sensitivity of the Sahara Desert to changes in past climate. They explain how this sensitivity affects rainfall across north Africa. This is important for understanding the implications of present-day climate change (driven by human activities). Warmer temperatures in the future may also enhance monsoon strength, with both local and global impacts.
Earth’s changing orbit
The fact that the wetter periods in north Africa have recurred every 21,000 years or so is a big clue about what causes them: variations in Earth’s orbit. Due to gravitational influences from the moon and other planets in our solar system, the orbit of the Earth around the sun is not constant. It has cyclic variations on multi-thousand year timescales. These orbital cycles are termed Milankovitch cycles; they influence the amount of energy the Earth receives from the sun.
On 100,000-year cycles, the shape of Earth’s orbit (or eccentricity) shifts between circular and oval, and on 41,000 year cycles the tilt of Earth’s axis varies (termed obliquity). Eccentricity and obliquity cycles are responsible for driving the ice ages of the past 2.4 million years.
The third Milankovitch cycle is precession. This concerns Earth’s wobble on its axis, which varies on a 21,000 year timescale. The similarity between the precession cycle and the timing of the humid periods indicates that precession is their dominant driver. Precession influences seasonal contrasts, increasing them in one hemisphere and reducing them in another. During warmer Northern Hemisphere summers, a consequent increase in north African summer rainfall would have initiated a humid phase, resulting in the spread of vegetation across the region.
Eccentricity and the ice sheets
In our study we also identified that the humid periods did not occur during the ice ages, when large glacial ice sheets covered much of the polar regions. This is because these vast ice sheets cooled the atmosphere. The cooling countered the influence of precession and suppressed the expansion of the African monsoon system.
The ice ages are driven by the eccentricity cycle, which determines how circular Earth’s orbit is around the sun. So our findings show that eccentricity indirectly influences the magnitude of the humid periods via its influence on the ice sheets. This highlights, for the first time, a major connection between these distant high latitude and tropical regions.
The Sahara acts as a gate. It controls the dispersal of species between north and sub-Saharan Africa, and in and out of the continent. The gate was open when the Sahara was green and closed when deserts prevailed. Our results reveal the sensitivity of this gate to Earth’s orbit around the sun. They also show that high latitude ice sheets may have restricted the dispersal of species during the glacial periods of the last 800,000 years.
Our ability to model the African humid periods helps us understand the alternation of humid and arid phases. This had major consequences for the dispersal and evolution of species, including humans, within and out of Africa. Furthermore, it provides a tool for understanding future greening in response to climate change and its environmental impact.
Refined models may, in the future, be able to identify how climate warming will influence rainfall and vegetation in the Sahara region, and the wider implications for society.
Edward Armstrong is a postdoctoral research fellow, University of Helsinki