Why are ambitious, planet-critical research proposals, still hitting funding roadblocks, and what will it take to break down these barriers before it’s too late?

It depends upon what country you are from.  For those in the US, politics determines, to a large degree what is funded, and politics is ultimately at the whim of the citizenry. Consequently, community outreach and engagement is critical.  That is a tough sell, however, as social media influence is challenging. 

What do you imply by planet-critical research proposal. All proposals are critical in one way or the other. It is only that researchers think of results rather than who to get the results.  They think more on the solutions instead of the methods/ study designs that would give them the much needed results. Why should we think of climate mitigation measures while we only think of planting trees (afforestation) instead of having a holistic approach of stoping flood waters from washing the top soil (rip erosion) needed by farmers for their crops; having structures to harnessing flood waters and recycle it into farm use or treated for drinking.  We think of carbon credits which is far fetched and not dealing with the immediate problem thus having an ambitious proposal that would definitely not get funding. Innovations/ discoveries take place in small unthought of aspects of life, so if planet crucial research proposals are to be funded, they need to consider solving simple but but needed current problems. 

We underfund planet-threatening climate science because traditional funding is risk-averse, short-term, and siloed between disciplines. Bold solutions all too often seem too hesitant or time-consuming for dominant models. To correct this, we need mission-focused funding agencies, public-private partnerships, outcome-based incentives, and long-term investments that reward impact over rapid returns.