An increase in carbon dioxide content in the atmosphere would not cause an abundance of desert plants.
Explanation:
Greenhouse Effect:
Carbon dioxide is a greenhouse gas, meaning it traps heat in the atmosphere. Increased levels of carbon dioxide enhance this greenhouse effect, trapping more heat and leading to a warmer global temperature.
Photosynthesis Enhancement:
While increased CO2 can initially stimulate plant growth and photosynthesis due to greater availability of the carbon substrate, this is a complex interaction. The overall impact on plant growth and ecosystem changes depends on various factors like temperature rise, water availability, and other environmental stresses.
Global Warming:
The rise in global temperatures caused by increased carbon dioxide concentration in the atmosphere is termed “global warming”.
Desert Abundance:
Higher temperatures and changing precipitation patterns due to climate change are likely to negatively impact desert ecosystems. Extreme heat and water scarcity can further limit the growth and abundance of desert plants. Therefore, an increase in carbon dioxide, leading to global warming, would not promote the abundance of desert plants.
Why other options are incorrect:
(a) more heat to be retained by the environment:
This is a direct consequence of increased carbon dioxide in the atmosphere. The greenhouse effect, where carbon dioxide traps heat, is the reason for global warming.
(b) increase in photosynthesis in plants:
Plants use carbon dioxide for photosynthesis. Higher levels of atmospheric carbon dioxide can initially enhance photosynthetic rates in many plants. However, this enhanced photosynthesis doesn’t negate the overall warming impact of increased CO2.
(c) global warming:
As explained above, increased carbon dioxide concentration directly causes global warming.