Final answer:
An important assumption regarding future carbon emissions is that they will continue to rise unless action is taken to reduce greenhouse gas emissions. This is due to the world's heavy reliance on fossil fuels and the long-lasting impact of greenhouse gases in the atmosphere. Various estimates and simulations support this assumption.
Step-by-step explanation:
An important assumption regarding future carbon emissions is that if no action is taken to reduce greenhouse gas emissions, they will continue to rise. This is because the world is heavily dependent on fossil fuels and the greenhouse gases emitted from these fossil fuel sources will persist in the atmosphere for decades or even centuries, further influencing Earth's climate in the future. This assumption is supported by various estimates and simulations that show the potential increase in CO2 levels and its impact on global temperatures by the year 2100.