One of the primary concerns withhydrogen is its production process, which often involves the use of fossil fuels such as natural gas. This means that, while hydrogen itself may be clean and emission free, the process of creating it is not. Additionally the distribution of hydrogen can be challenging due to the need for specialized infrastructure, which can be costly to build and maintain.

By contrast, fossil fuels are already well-established as a source of energy, and infrastructure for their production, transportation, and use is widely available. However, the environmental impact of fossil fuels is well documented, with greenhouse gass emissions contributing to climate change and other negative impacts on the environment. 

Despite these concerns, some argue that the switch back to fossil fuels could actually be beneficial in certain circumstances. For example, in areas where infrastructure for hydrogen production and distribution is lacking, a switch to fossil fuels could provide a more efficient and cost effective means of meeting energy needs. Similarly, in regions where renewable energy sources are not yet fully developed, fossil fuels may be a necessary stop gap measure.

Ultimately, the decision to switch from hydrogen to fossil fuels should be made on a case by case basis, taking into account a range of factors including local energy needs, available infrastructure, and environmental concerns. While both hydrogen and fossil fuels have their advantages and disadvantages, it is clear that the future of energy production will require a diverse mix of sources in order to meet the needs of a growing global population while minimizing negative impacts on the environment.