LARISSA RIBEIROPictures of floods, dried out forests and too much heat have become commonplace when one thinks about global climate change. The need for investment in alternative energy sources is also part of this context. What is not immediately obvious, however, is the role of chemistry in this issue. Yet it is everywhere, from the mechanism that leads to change to the solutions. This was highlighted by the climatologist Carlos Nobre, from the National Institute of Space Research (Inpe), the chemist Jailson de Andrade, from the Federal University of Bahia (UFBA), the molecular biologist Glaucia Souza, from the University of São Paulo (US), and the chemist Luiz Pereira Ramos, from the Federal University of Paraná (UFPR), at the first meeting of the International Year of Chemistry Conference Cycle, held in São Paulo, on April 4. The cycle, which goes until November, is an initiative of FAPESP and of the Brazilian Society of Chemistry, as part of the celebrations promoted by the International Union of Pure and Applied Chemistry (IUPAC) along with Unesco on the theme Chemistry: our life, our future.
The chemical connections leading up to climate changes also affect food production, as was shown by the chemist Arnaldo Alves Cardoso, from Unesp (the State University of São Paulo) at Araraquara and coordinator of the panel. The green revolution, which increased food production and yielded the Nobel Peace Prize for the US agronomist Norman Borlaug in 1970, was based largely on the synthesis of reactive nitrogen, which can be used as a fertilizer. However, the undeniable benefits also generated certain problems: the nitrogen surplus that ends up in rivers and the atmosphere is an important source of pollution and of the greenhouse effect.
LARISSA RIBEIROChallenges
“We’re living longer and better, but that isn’t true when it comes to the planet,” highlighted Jailson de Andrade, who stressed the importance of investing in sustainability. According to him, energy, water and food production are interconnected challenges. “And there isn’t a single one of these challenges for which chemistry is not a core element.”
Concerning energy, the researcher from Bahia showed that there is no single solution. Society is fearful of nuclear fission, especially now that the nuclear accident in Japan is fresh in the collective recollection of things. In any event, to replace the fuel consumed in the world today it would be necessary to build 10 thousand nuclear power stations over the next 30 years (i.e., one a day), which is obviously impossible. Andrade also stressed that fusion, a different way of producing nuclear energy and one that might carry fewer risks in its wake can only be conducted on a experimental scale. In addition, hydrogen fuel cells are still too expensive. Solar power shows great promise, but it is necessary to raise the efficiency of the photovoltaic cells, which can only convert 30% of the solar energy they get into electricity at present. “We are still hunter-gatherers of energy, but we must become producers,” he warned.
Part of the energy solution may lie in biofuels, which is what Bioen, the FAPESP Program of Research into Bioenergy, is betting on. Here, according to Glaucia Souza, the program’s coordinator, Brazil is advancing by leaps and bounds. “We may manage to replace 30% of the gasoline used worldwide,” she stated.
Improving production does not depend solely on expanding the area of sugarcane plantations and building more mills, but also on improving productivity. This is the mission of the Bioen research projects. The group led by the USP researcher is involved with improving sugarcane genetics using cutting-edge genetic knowhow. “Sugar cane is the greatest of genomic challenges,” said Glaucia, “because the hybridization conducted during the course of developing a variety capable of yielding more sugar has multiplied the plant’s genome ten-fold.”
With the new sequencing technologies, progress is now far faster than in past decades, but merely revealing unconnected segments of the plant’s DNA is not enough. “We’ve already sequenced 70% of the gene-rich areas, but with 10 copies it’s difficult to put this genome together,” she explained. One must also understand the functioning of this genetic material to be able to interfere with it by switching genes on or off in order to improve productivity under various circumstances, such as obtaining greater sugar storage without stepping up irrigation or hampering plant growth.
Along with biorefineries that should emit no carbon and use all the sugarcane byproducts, an issue that concerns one of the areas of Bioen, this vegetable, which is highly efficient in producing and storing sugar, might lead to important changes in the energy structure of the country and the world.
The Bioen programs make it clear that vegetable fuel is much more than the energy-rich juice of plants, a view shared by Luiz Ramos, from UFPR: soy, cotton, palm oil and physic nut (Jatropha curcas), among others, are possible biodiesel sources. At the laboratory in Paraná state, researchers have tried to develop technologies based on high performance reactive catalysts that might improve the production of ethanol and biodiesel, reducing the pollutants emitted by this industry.
The production of second-generation ethanol is yet one more line of research at Ramos’ laboratory. “We managed to use steam explosion to transform sugarcane bagasse more selectively and efficiently.” The process destroys the structure of the cell wall, as a result of which cellulose becomes more readily available for the generation of energy. It is not an unprecedented process, but the group innovated by using a catalyst and auxiliary chemicals to make the process more effective.
The use of insoluble catalysts in the process, the so-called heterogeneous catalysis, is the backbone of part of the research of the Paraná group. “The environmental and economic impact is far lower when the catalysis is truly heterogeneous,” explains the researcher, who has established partnership agreements with firms to offer chemical solutions for the bottlenecks in biofuel production.
Eduardo CesarHuman era
Better technology to produce biocombustibles, using more renewable energy sources, might transform Brazil into a tropical environmental power, stressed Carlos Nobre. Hydroelectric power, which accounts for most of the country’s power consumption, with 46% of renewable sources, is not enough. According to him, the country is lagging behind in terms of wind and solar power, resources in which it is particularly wealthy. He says that photovoltaic energy should become a more widely disseminated source of energy, including the generation of hydrogen as fuel. “We’re lying in a splendid cradle,” he states, paraphrasing Brazil’s national anthem. Every hour, 9 thousand people are born, 4 million tons of carbon dioxide (CO2) are emitted, 1,500 hectares of forests are cut down, 1.7 million kilograms of reactive nitrogen are added to soil and water, and 3 species become extinct. “We have gone way beyond the limits of sustainability.”
Excess carbon dioxide, which has become the global warming icon, is not the only villain of these limits that have been far exceeded: other gases add to the greenhouse effect, such as nitric oxide and methane. These substances, in excess in the atmosphere and the oceans, have already started causing damage. However, abrupt and substantial increases in recent decades have made global warming an unequivocal point, according to the Inpe climatologist. “Chemistry must find a feasible way of removing CO2 from the environment,” he warned.
Investments with this aim must be made before the terrestrial system exceeds its so-called tipping point, when return to the preceding state becomes impossible. “If we go beyond such points, all discussions become merely academic.” One such example concerns CO2 yet again. Every year, human activity accounts for an added 9.7 billion tons of this gas, of which 5.5 billion are absorbed by the oceans and the plants. This addition is responsible for the acidification of seawater, which might have serious consequences. If the process continues at its current pace, it is estimated that by 2100 the pH of the oceans could reach 7.8. Under these conditions, he warned, aragonite can no longer be formed, and it is an essential substance for a large part of the marine organisms with a bone structure.
Concerning the Amazon region, Nobre’s research has shown that average warming greater than 3.5 degrees Celsius (°C) and more than 40% of deforested area would push the rainforest beyond the point of no return, disseminating a process known as savannization. There is still time to reduce the damage, according to the Inpe researcher and member of the Intergovernmental Panel on Climate Change. However, the political and behavioral changes are not occurring at the speed that science deems necessary.
To limit warming to the 2°C recommended by the IPCC, the entire world cannot emit more than 500 billion tons of carbon until the end of this century. This would require a reduction of current emissions, but the negotiations are slow. However, Nobre sees the leadership of the reduction in greenhouse gases emission that Brazil embraced at the Copenhagen Climate Conference, COP-15, in late 2009 as a positive sign.
Chemistry is part of the consolidation of this leadership, according to the experts who, at these early April conferences, were applying different approaches to the same problem. Building a bridge between biology and physics, between urbanization and the environment, this field of knowledge may turn out to be the key, in the next few decades, to making human life with its present-day characteristics sustainable. The conference cycle is a valuable opportunity to discuss how this field of knowledge can help to solve major global challenges and to arouse the interest of young people in scientific investigation. See the full program here.
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