Computer Models Of Civilization Offer Routes To Ending Global WarmingClick to enlarge the image toggle caption STR/AFP via Getty ImagesThe world's most respected climate scientists issued a warning this week. However, they insist that there is still a chance for the world to avoid the worst effects.Ko Barrett, vice-chair of the Intergovernmental Panel on Climate Change, stated that it is possible to prevent most of the devastating impacts. However, this requires unprecedented, transformative change. "I believe that the idea that there is still a way forward is something that should give us hope."Computer simulations of the global economy have created a hopeful path that will eventually see dangerous climate changes stop. These models are called integrated assessment models. There are about a dozen versions: one developed in Europe, four in Japan and one at the Pacific Northwest National Laboratory in the United States."What we do most is to try to find the best way to achieve the Paris goals." Detlef van Vuuren from the Netherlands Environmental Assessment Agency (NeA) developed one of these models.How to reduce greenhouse gas emissions by reducing them to zero within 40 yearsParis was the meeting point for world leaders who agreed to limit global warming below 2 degrees Celsius (3.6 Fahrenheit). The planet has warmed by about 1 degree Celsius compared to preindustrial levels.This goal would mean reducing net greenhouse gas emissions by zero in 40 years. It would require significant changes, so it is not immediately obvious that it is possible.Van Vuuren and his coworkers turned to their computer models to help them. "How can we achieve zero emissions?" He says. He said, "That's transportation, that's housing, that is electricity."Each model starts with data on current greenhouse emission sources. These include automobiles and buses, planes, power plants and home furnaces as well as cars and buses. These models include assumptions about international trade, prices, as well as the costs of new technologies.The scientists then force the virtual worlds to alter their course by setting limits on greenhouse gas emissions. As long as the technology is feasible, the models will try to meet that requirement as cost-effectively as possible.The good news is that models were able to achieve this target in situations where the world governments were willing to cooperate to fulfill their Paris commitments. According to Keywan Riahi from the International Institute for Applied Systems in Austria, there were multiple routes to zero carbon.He says, "The models tells us that there are first and foremost alternative routes possible; that there is a range of choices for the decision-maker."Different models and assumptions can lead to different visions of the future. They're all drastically different from today's situation.Some models show how people respond to rising energy prices and government regulations by altering their lifestyles. They shift to energy-efficient homes and use public transit instead of their cars. Autonomous vehicles, which can be driven by humans and take them to their destinations like Uber, are an alternative to traditional bus lines.Riahi prefers this version. He says, "I am convinced that a fundamental demand side restructuring would also lead us to a higher quality of life."Others show that people are still using a lot of energy. This in turn calls for a massive increase in the production of clean electricity. This would result in 10 to 20 times more land being covered by solar and wind farms than currently, and more power plants that burn wood or other fuels equipped with equipment to capture carbon dioxide and store it.Models could be hampered by politics and individual preferencesRiahi quickly points out that the models might not work in real life. They do not account for political obstruction or human preferences. Even though the model suggests otherwise, people may choose to drive a luxury car over public transit.However, the models can also be too optimistic about technological innovation. Van Vuuren claims that ten years ago they didn't anticipate the rise in cheap solar power. "We are extremely lucky that renewable energy costs have fallen rapidly over the past decade," van Vuuren said. This has made it much easier to reduce carbon emissions.Despite their flaws, they remain the main way scientists and policymakers can determine the best options for the future. These models quantify tradeoffs and the consequences of decisions that might not be obvious. For example, if countries want to convert trees or crops into energy, this means that they will need less land for food production or natural forests. The models also show that international cooperation is crucial, with rich countries helping to reduce their emissions.Computer modeling results are similar to fuzzy maps. They point out possible routes that could save the world from disaster.