Scientists, here's the bottom line. If you don't convince the public that your science matters, your funding will quickly vanish and so will your field. Put another way, the era of outreach being optional for scientists is now over.Researchers have been able to cloister within an academic ivory tower - conducting their research without paying much attention to what's going on in the wider world - only because there has been a relatively stable funding base for science. Governmental sources have been vital to that funding base, particularly for basic research where the government .Unfortunately, the stability of that funding is now a thing of the past. Thanks largely to the federal budget sequester, research outlays by the governmentin just this fiscal year. And political leaders have further changes in mind, such as potentiallyof the kinds of research that the government will fund.These tremors in the science funding landscape are just the beginning of what is to come. What is driving all of this is a two-front budgetary squeeze, the likes of which have never been seen in the history of the United States. In short, retirement and health care spending are eating the federal budget alive, leaving fewer and fewer dollars for everything else that the government buys (like research).Americans are aging as a population, which means more and more are receiving retirement checks through Social Security. Social Security's share of the federal budget has doubled since 1963: 11% of the budget then, 20-22% of the budget for the rest of this decade (budget figures in this post come from a ).Federal dollars spent on health care have exploded even faster, not just because more and more Americans are eligible for Medicare and Medicaid, but also because the per-person costs for health care keep climbing. In 1970, 4.9% of the federal budget went to Medicare and Medicaid spending. By 2011, that share had more than quadrupled to 23.2%. And the numbers keep rising, with federal health care spending expected to eat just under a third of the budget (32.8%) within the next ten years. To make matters worse, retirement and health care spending are on autopilot. For other parts of the budget - defense, national parks, research, etc. - the government decides every year how much to spend. Retirement and health care spending aren't like that. They are considered mandatory spending and the amounts spent on them are essentially based on preassigned formulas that are extremely politically difficult to change. Mandatory spending (which mostly consists of health care and retirement spending) continues to ratchet upward and is projected to soak up well over sixty percent of the federal budget within the next ten years.Everything else in the federal budget, from new aircraft carriers to food inspections to the National Science Foundation, is facing an ever-more dire squeeze. As a consequence, every program needs to fight like crazy to defend its place in the budget - or find itself out of the budget altogether.A key part of this budget defense is making the case directly to the American people about why they should care about your program. Take the F-35 for example, a new fighter aircraft being developed for the military at the cost of billions of dollars a year. Even though the manufacturer Lockheed-Martin employs an army of lobbyists on Capitol Hill, the company still sees the needthey ought to keep the F-35 funded.The scientific community must also do the same, by convincing the public that it is worth spending tax dollars on research. Scientists: this isn't someone else's job - this is your job, starting immediately. If you personally hope to receive government research funds in the future, public engagement is now part of your job description. And if you and your colleagues don't convincingly make the case to the public that your discipline should be funded, well then it won't be. Without a public broadly supportive of funding science, it is all too easy for politicians looking for programs to cutas an excuse to further slash science funding.How do we as scientists convince the public that our science is worth funding? The answer is simple: consistently engage people with our science. Almost all scientists care deeply about their research. All we need to do is to frequently share that passion with a broader audience, in any of a hundred ways. We can giveabout our science. We can write . We can put together . Honestly, it doesn't really matter what method we use, so long as we connect to the public on a frequent basis with our science. And that consistency of engagement is key, because we can't build a constituency for anything on a one-off basis.All scientists must do much more right now to build a broad base of public support for science funding. If we don't - if we close our eyes to the fact that the federal budget is in absolute crisis - we could easily see government support for research quickly fade to a shadow of what it is now. If research spending is crippled, it isn't just our careers on the line. It's the future of scientific innovation in this country and this world that are imperiled. We simply can't let that happen. Let's get to work.--------------------------------------------------------------------On April 30th, COMPASS publishedon the journey from science outreach to meaningful engagement. This post is part of a series of reactions, reflections, and personal experiences we hope will expand the conversation. Read the , or track the conversation by searching on Twitter for . Followon Twitterand . 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