Biodiversity is being lost at a rate not seen since the last mass extinction. but the united Nations decade-old plan to slow down and eventually stop the decline of species and ecosystems by 2020 has failed. most of the plan’s 20 targets - known as the Aichi biodiversity targets - have not been met. the Aichi targets are part of an international agreement called the UN Convention on Biological Diversity, and member states are now finalizing replacements for them. Currently referred to as the post-2020 global biodiversity Framework (gbF), its draft was published in July 2021. it aims to slow down the rate of biodiversity loss by 2030. And by 2050, biodiversity will be “valued, conserved, restored and wisely used, maintaining ecosystem services, sustaining a healthy planet and delivering benefits essential for all people”. the gbF is a comprehensive plan. but success will require systemic change across public policy. that is both a strength and a weakness. if systemic change can be implemented, it will lead to real change. but if it cannot, there’s no plan b. this has led some researchers to argue that one target or number should be prioritized and defined in a way that is clear to the public and to policy makers. it would be biodiversity’s equivalent of the 2°C climate target.

According to the passage, why do some researchers advocate that one biodiversity target be prioritized?

The correct option is: Systemic policy change is difficult to implement

Step-by-Step Explanation:

1. Analyze the passage for key terms: The question asks why some researchers advocate for prioritizing a single biodiversity target (similar to the 2°C climate target).

2. Locate the relevant section in the text: Towards the end of the passage, it states:
"the gbF is a comprehensive plan. but success will require systemic change across public policy. that is both a strength and a weakness. if systemic change can be implemented, it will lead to real change. but if it cannot, there’s no plan b. this has led some researchers to argue that one target or number should be prioritized..."

3. Synthesize the reasoning: The passage highlights that implementing systemic change across public policy is challenging (a potential weakness/difficulty). Because there is no "Plan B" if such widespread systemic change fails to be implemented, researchers suggest focusing on a single, clear prioritized target to make it easier for the public and policy makers to understand and achieve.

4. Evaluate the options:
- Systemic policy change is difficult to implement: Correct, as the difficulty/uncertainty of implementing systemic change is the primary reason given for suggesting a single prioritized target.
- Post-2020 global biodiversity Framework (gbF) is comprehensive: Incorrect, this is mentioned as a fact, not the main reason for needing a single target.
- the 2 °C climate target needs to be prioritized: Incorrect, the 2 °C target is merely used as an analogy/equivalent example.
- biodiversity needs to be valued, conserved, restored and wisely used: Incorrect, this is a general goal of the GBF by 2050, not the specific rationale behind advocating for one single target.