What happens if the human population continues to grow and nothing much changes in the way we curb fossil fuel use?
Climate models these days have largely focused on scenarios that assume some level of restraint on greenhouse emissions, with particular emphasis on the political goal of keeping global temperatures no higher than 2 degrees above pre-industrial levels. But scientists at the National Center for Atmospheric Research in Boulder and the Institute for Atmospheric and Climate Science in Zurich have simulated scenarios that show the upper boundaries of future greenhouse gas emissions.
In a paper published recently in the journal Environmental Research Letters, the scientists write that understanding these upper range scenarios is crucial for good decision-making about climate change.
In one climate scenario, the human population grows from 6 to 11 billion by the end of the century, while energy supplies gradually shift from today’s heavy reliance on fossil fuels to 30 percent from carbon neutral sources (compared to 14 percent in 2000). The higher demand for energy results in 55 Gigatons of carbon per year by 2100, which is similar to the highest nonintervention emissions scenarios in existing published literature. In other words, more and more people on ...