What practicable alternative do I have to not fly around the globe to present a poster/pollute environment? Popularizing your research and results is an important part of a non-tenured researcher, which alreday and often starts after graduating with a bachelor and proceeds up to being a postdoc for many years. While I don't question organization of conferences at all, observing that sometimes several researcher from one group fly to a conference, many only to present a poster sometimes, made me think, if there are alternatives to personally choose and practice as I'm also interested in the Azimuth project. I also remember from mail contacts with other researchers some of their signatures asking the recipient kindly "to not print out this mail" and increase its ecological footprint, as digitalization sadly increases paper consumption (tragic "fun" fact).

So my question is, what practicable best option/alternative do I have: 


asking colleague of my group with talk to hang up my poster/present it/point to mail/phone for interested viewers
directly mail-spam attendees of the conference (looking up program) I know from papers in my field before conference with a PDF version of my poster, not paying conference fee (which look to me often also rather like a business model also among important and renonwed conferences fostering so many predatory conferences I get notice in my spam folder, likely being financed in very costly conference venues by many "poster-boys")
not care about my ecological footprint because researchers are no role-models and just a very small number of the international air traffic. As said, I don't question talks and invited talks held in front of several dozen peers.
only present posters for few years to make my community aware of myself or only at nearby locations.
engage in online conferences (which seem totally unpopular, not in practice in my field of condensed matter physics, being no niche and staging dozens of conferences even in single subfields like magnetism, materials...)
...


I know, there will be some disadvantages. Actually, the last idea originating from a discussion at a poster on the other side of the globe made me writing a granted research proposal which will finance my post-doc position and a PhD-student. But I think it would have been just a matter of more time and didn't need a flight around the world.

EDIT: I'm really looking for practicable tips one can apply now instead of waiting until the organization of conferences will hypothetically significantly change like in this related question. It's highest voted answer is funny, but has been disproven for decades as the environmental pollution steadily increases and unfortunately human kind and environment have a "time limit" :-)
If you want to build a strong career and be noticed internationally, then you probably have little choice but to attend international conferences in the present situation.

Longer term, however, you can try to work toward a world of virtual conferences rather than ones requiring physical presence, though these have tradeoffs. But the current and future communication technologies will make them more practical as time goes on. 

But, there are other things to consider than just the carbon-cost of air travel. First, the plane will fly anyway even if you aren't on it. Collective political action can work toward a world with less air travel, of course, but an individual has little real effect. The carbon cost of air travel is amortized over a large number of people, of course, and if they don't fly they still don't have zero carbon usage. Depending on your normal activities and travel (to work, say) needs, a week long conference across the pond may not cost you much in carbon, if there is little travel at the conference site and things are centralized. 

But if you do travel, there are things you can do to better utilize the benefits of the costs you incur. Making arrangements before you go to work with international colleagues for a few days before or after the conference helps amortize the cost over a larger set of activities, chaining the cost/benefit ratio. 

You can, of course, think globally about your carbon usage and find other ways to reduce your footprint so that, even as an individual, you have a minimal negative impact. 

Also, communication technologies aren't carbon-free. The trade-off computations are very complex, in fact. I just read a report that says that streaming movies, for example, has a higher carbon footprint that pressing and distributing DVDs due to the energy required by servers (a continuous cost) vs the pressing/distribution cost (discrete). 

Our climate issues are a result of bad choices by society as a whole, making better solutions difficult or impossible to employ by individuals. An individual has little effect, especially if they are conscious of the problems and take steps to limit personal use where possible, but also to demand better overall solutions of governments and other large institutions.