This is the price tag: $20.8 trillion. Because there is currently no way to stop or slow Alzheimer’s, that’s what we will all pay over the next generation to care for people with Alzheimer’s unless policymakers change the disease’s trajectory by adequately funding research for treatment.

At $20.8 trillion, Alzheimer’s will cost America more over the next 36 years than the total federal debt accrued over the last 36 years ($17.4 trillion). And, it is Medicare that will bear the greatest burden; so much so that Alzheimer’s could bankrupt the federal insurance program.

A new report from the independent research firm The Lewin Group, commissioned by the Alzheimer’s Association, finds that on the current trajectory Medicare spending to care for people with Alzheimer’s and other dementias will increase more than fourfold to $589 billion in 2050. That’s one of every $3 Medicare will spend in 2050, and nearly what we spend on all of Medicare today.

The daunting numbers come from the fact that the number of Americans ages 65 and older living with Alzheimer’s disease will triple in just over a generation. Worse, more of them will be in late-stage Alzheimer’s in 2050 than the total number of Americans with the disease today. These individuals will lose their ability to eat, bathe and manage bodily functions, and require constant care for years on end, until the disease finally kills them.

According to the New England Journal of Medicine, Alzheimer’s is already the nation’s most expensive disease. The nation and the federal budget clearly cannot afford to let Alzheimer’s stay this course, which is why there is bipartisan agreement to change it.

The 2011 National Alzheimer’s Project Act required the development of the country’s first-ever national Alzheimer’s plan. Released in 2012, the National Plan to Address Alzheimer’s Disease set a clear goal: “prevent and effectively treat Alzheimer’s disease by 2025.”

Hitting this target would rewrite the future, saving millions of lives and trillions of dollars. For example, a treatment to delay the onset of Alzheimer’s by five years introduced in 2025 would decrease the number of Americans with Alzheimer’s by 2.4 million by 2030, according to the report.

That’s five more years with our loved ones, earned insights, proud independence and cherished memories.

There is hope. A federal research investment of $2 billion a year between now and 2025, as suggested by the scientific community, would be recouped in the first three years after a treatment became available. And, the savings would grow substantially over time. If we hit the target set by the National Alzheimer’s Plan’s 2025 goal, there will be a total savings of $220 billion over the first five years, and by 2050 the savings would grow to $367 billion in just a single year.

Promising research is ready for the pipeline, and prominent scientists believe the national goal is attainable if we accelerate funding. While the president’s budget again prioritizes Alzheimer’s, the scale of funding proposed is not commensurate with the triple threat that Alzheimer’s poses — soaring prevalence, lack of treatment and enormous cost.

With millions of lives and trillions of dollars at stake, we need real progress in the fight against Alzheimer’s.

To guide research funding, Congress passed the Alzheimer’s Accountability Act as part of the fiscal 2015 Omnibus Appropriations Bill. It directs the National Institutes of Health to submit a Professional Judgment Budget to Congress that reflects the state of Alzheimer’s knowledge and the research investments NIH scientists say are required to meet the 2025 goal.

When the NIH scientists speak, it is vital that Congress listens and acts with urgency. Congress has the power to change the trajectory of Alzheimer’s, saving lives — and Medicare.

Harry Johns is president and CEO of the Alzheimer’s Association, the world’s leading voluntary health organization in Alzheimer’s care, support and research.He wrote this for CQ-Roll Call magazine.