The government shutdown is now in day 19 and shows no sign of ending.

The shutdown is already having an effect on government agencies, including closures and delays.

But as the shutdown drags on, the effects will only get worse.

Millions of Americans could start losing access to rent assistance and food stamps, airport security will get worse, and damage to national parks could increase.

Despite daily negotiations between the two sides, neither President Donald Trump nor Democrats appear to be close to backing down in the battle over the government shutdown.

The shutdown, which Trump kicked off by refusing a bipartisan, short-term funding extension before Christmas, appears poised to challenge the record for the longest federal funding lapse in the modern budgeting era.

Already, the shutdown is starting to affect federal departments that are currently without funding. Everything from the National Zoo's panda cam to paychecks for hundred of thousands of federal workers have become affected.

Read more: Here's what happens to Social Security and disability benefits during a government shutdown»

As the shutdown drags on, the fallout will only get worse. Many key programs are running on reserve funds during the month of January. When those wells run dry, everything from rent assistance to food stamps could be cut off.

Here are a few examples of how a lengthy shutdown could get worse: