Final answer:
An increase in atmospheric carbon dioxide would not directly increase the abundance of desert plants. While CO₂ levels can influence photosynthesis, the specific adaptations of desert plants to their environment can limit their response to such changes, and global warming may worsen water scarcity which is detrimental to plant growth.
Step-by-step explanation:
An increase in carbon dioxide content in the atmosphere would not cause an abundance of desert plants. When CO₂ levels rise, the atmosphere retains more heat due to the greenhouse effect, leading to global warming. The enhanced greenhouse effect results in higher surface temperatures which, in conjunction with other climate changes, can disrupt ecosystems and lead to a variety of effects on plants.
Higher CO₂ levels can stimulate photosynthesis in plants up to a point, as CO₂ is a raw material for the process. However, the relationship between CO₂ concentration and photosynthesis is complex and can be influenced by other factors such as temperature, water availability, and nutrient levels.
In contrasting environments, like deserts, higher temperatures and altered precipitation patterns can exacerbate water scarcity, hindering plant growth. Moreover, the specificity of desert plant adaptations to their environment means that a sudden increase in CO₂ might not directly translate to an increased abundance of desert plants, as these species are adapted to very specific, arid conditions.