I think designers have the responsibility of the sustainability of design because what we make informs the user on what is inside and we have the chance to influence what the consumer does with the package it came in. Our job as designers is to communicate with the viewers so we are responsible to communicate what to do with the package once you are done.
I think the best example from my personal experience is Hello Fresh. The box that they ship their products in has a clear and fun design with its lime green appearance excites the customer for their meals inside. The box contains information on what is recyclable and how to recycle it. For example, the ice bag that sits on the bottom of the box keeping the ingredients cold tells the customer to thaw, empty the contents into the trash, and recycle the bag that it came in. The box has graphics on them so the boxes had to been shipped in another protective box to protect the design so the fact that they advertise and project how much of the packaging is recyclable makes up a bit for the extra trash and landfill that the company creates.
I have found that humans are inherently lazy. Most people will take the path of least resistance through life. There is an icon for things that are recyclable that is pretty much universal. Almost anyone in the this country can look at the triangle of arrows pointed at each other and know that it is in fact recyclable, but not everyone is actively looking for them. A designer practicing sustainability responsibility will make these marks highlighted to tell the user to recycle the product once you are done with it.
Another problem I found with the issue of landfill and lack of recycling is the absence of knowledge of how to recycle objects. Some people still throw pizza boxes in the recycling bin and has to be thrown away along with the rest of your recyclables. I think graphic designers or just designers in general can build a more intuitive system to get more people to recycle. This can be done with more clear signage or city planning that has accessible recycling centers.
Graphic designers usually do not see the environmental impact that our work actually has. There have to be cloud server computer farms, printing facilities, packaging companies, and what the user will do with the final project. Knowing this, designers should find a way to encourage the companies they are working for to produce their designs in sustainable ways, as well as making their packages or designs with directions on recycling.