The problems plaguing the American prison system have grown too large to be ignored. The conversation on prison reform has broken into the mainstream, and the need for reform commands wide support across the political spectrum. There seems to be a burgeoning consensus that the manner in which the country incarcerates criminals is overly punitive and ineffective as a vehicle for rehabilitating its inmates.

The prison system is indeed in dire need of a fundamental transformation — perhaps even more than you think. Here's a roundup of some of the most jarring data points that illustrate how bad things have gotten:

1. The population of those in prison and jail would be the fourth largest city in America.

Source: Prison Policy Initiative / U.S. Census Bureau

These stunning statistics come via the Atlantic: "Today, like any other day, there are around 2.4 million people incarcerated in America's federal, state and local prisons and jails. Together, the nation's inmates would constitute the fourth biggest city in the United States, knocking Houston down a notch. Expand that grouping to everyone under correctional control, including probation and parole, and you'd have a metropolis of nearly 7 million, second only to New York.

"Finally, reunite the number of people that see the inside of a jail cell in a given year, and you'd have a prison city with a population as big as New York and Los Angeles combined (11.6 million)."

How do these numbers stack up globally? The U.S. has the largest incarceration system in the world. It has one-fourth of the world's prisoner population despite having only 5% of its entire population.

2. The prison population has increased 400% since the Reagan presidency.

The Sentencing Project

Between 1980 and 2010, the prison population increased fivefold, according to the Sentencing Project. Several factors contribute to this rise, but mainly it can be explained by a response to a spike in the crime rate (which occurred from the mid-1970s through the early 1990s), more convictions, harsher sentences and the sharp escalation of the war on drugs. In the past few years, the prison population has decreased ever so slightly.

3. Over 3,000 prisoners are serving life without parole for nonviolent crimes.

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The American Civil Liberties Union's 2013 report "A Living Death" documented 3,281 prisoners who have been slapped with life sentences without parole for nonviolent crimes, including shoplifting a jacket, stealing gas from a truck and selling $10 worth of marijuana. About 65% were black and many were struggling with mental health issues.

Life without parole as a general practice was extreme enough that the sentence was rarely issued prior to the 1970s. But its use has grown in the past few decades: The number of convicts receiving it quadrupled nationally between 1992 and 2012, according to the ACLU.

4. The incarceration rate of black men in the U.S. dwarfs even that of South Africa under apartheid.

Prison Policy Initiative

As Michelle Alexander laid out in the New Jim Crow, her groundbreaking tome on the racialized nature of mass incarceration, the U.S. imprisons black men at about five times the rate that South Africa did during apartheid. Another way to consider the scope of the incarceration system in the lives of African-Americans: More black adults are held captive by correctional apparatuses today — in prison or jail, on probation or parole — than under slavery in 1850.

5. The U.S. spends far more imprisoning its citizens than educating them.

Vera Institute of Justice/U.S. Census data

This GIF, using data from the Vera Institute of Justice's 2012 "Price of Prisons" report and 2012 U.S. Census data on public school costs, shows how much more 40 states spend on their prisoners than on their K-12 students. Keeping someone in prison costs five times more than educating students in California, Washington and Utah, and in many other states is at least double or triple the cost. (The states not included above did not complete the survey.)

6. A massive drop in the crime rate did not slow the pace of mass incarceration.

The Sentencing Project

The crime rate grew from the 1970s until the early 1990s, but after that it plunged. Incarceration rates increased steadily from the 1970s, but after the crime rate began to fall, it continued to climb unabated.

7. Over two thirds of people who leave prison will return

The Bureau of Justice Statistics' report on state prisoners in 2014 found that 68% of state prisoners were re-arrested fewer than three years after their release and 77% were re-arrested within five. When measuring the group arrested within five years, more than a third were incarcerated within their first six months.

8. In 17 states, prisons are filled beyond capacity.

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Seventeen states have prison populations that exceed the maximum capacity of their prison facilities. Overcrowding is a serious problem, creating hazards for the inmate population and encouraging irresponsible behavior by administrators. California, which typifies many of the worst traits of mass incarceration, was at one point shipping prisoners to private prisons in other states to lessen overcrowding that was so bad that, according to one federal judge's estimate, one prisoner was dying weekly as a result of medical neglect, according to the Huffington Post.

Barring sweeping reform, mass incarceration is likely to stay here for a while. As Slate notes, even the slight drop in the prison population in the past few years isn't something the concerned should bank on, as the current pace of decline would take about 90 years to bring the prison population back down to 1980 levels.

But as bleak as that sounds, there are reasons for optimism about the possibility for reform. The U.S. attorney general has called the current system "ineffective and unsustainable," and the need for reform is surfacing with greater frequency in the media and policy world. One sign that it has breached the mainstream is that the MacArthur Foundation, the influential institution that provides generous "genius grants" to creative thinkers every year, has recently partnered up with the Vera Institute of Justice to conceive of innovative ways for local governments to reform their jails, according to BuzzFeed. That kind of new energy bodes well for a long-standing problem.