Here is the letter I sent, which anyone is welcome to copy or borrow from when contacting their own representative. There is only a small bit that is UK-specific. My MP happens to be in the government party, but a small change of wording would work for representatives from opposition parties.
Today is International Day for Biological Diversity, so I am writing, as one of your constituents, to seek your response to the recent report for policymakers published by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). Here is a link to the report: https://www.ipbes.net/sites/default/files/downloads/spm_unedited_advance_for_posting_htn.pdf.
The report is the result of several years of systematic review by hundreds of experts. It describes the myriad ways in which biodiversity is essential for human and planetary wellbeing, the extent to which biodiversity and ecosystem services are being lost, the causes of this loss, and the transformative change required to get us back onto a sustainable pathway. The production of food is a central topic, both because changes in land use are one of the main drivers of biodiversity loss, and because such changes are shooting ourselves in the foot as biodiversity provides essential services such as pest control and pollination. The report is very clear that transformative change is required if we are to meet any of the current biodiversity targets, such as those in the Sustainable Development Goals, as well as targets on the closely intertwined topic of climate change. Changes are required in national/local environmental and agricultural policies, in foreign and international trade policies, and in our fundamental economic focus on growth rather than sustainability.
I would really like to hear how your government plans to make the necessary changes, particularly with respect to the forthcoming UK Environment Bill, but also in the broader areas of economic and international policies.
And here's the editorial: https://www.nature.com/articles/s41559-019-0922-2