You’ve heard the warnings: Global warming could doom humanity. Overpopulation and deforestation will destroy the planet. We’re going to run out of energy.

It isn’t happening right now, experts say, but it could happen in a few decades.

Yet, decades ago, experts warned that many catastrophes would happen now – by the year 2015. Yet they have not. FoxNews.com found five predictions that went astray.

1) UN overestimated global warming by 2015

Two decades ago, the UN came up with several models that all predicted that by 2015, the Earth would have warmed by at least a degree Fahrenheit. Yet in the last two decades, there has instead been virtually no warming according to satellite temperature measurements.

Most climate scientists say this is just a temporary pause and that warming will soon pick up again, though some say they now expect to see less warming in the future due to the pause.

2) All Rainforest Species Will Be Extinct

Dr. Paul Ehrlich, the President of the Center for Conservation Biology at Stanford University, got famous for his 1968 book “the Population Bomb” which predicted that increasing human populations would spell doom.

One part of that doom, he warned in his 1981 book “Extinction,” was that all rainforest species would likely soon go extinct due to environmental destruction.

“Half of the populations and species in tropical moist forests would be extinct early in the next century [the 2000s] and none would be left by 2025,” he warns on page 291. He added that that his model indicated that, on the upper bound, complete extinction would occur as soon as 2010.

Elsewhere in the book, he also wrote that his model’s assumptions were “more realistic” than those typically used and that “unless appropriate steps are taken soon… humanity faces a catastrophe fully as serious as an all-out thermonuclear war.”

Ehrlich did not respond to a request for comment Wednesday morning.

3) Oil will run out by 2015

A Pennsylvania state government “Student and Teacher Guide” reads: “Some estimates of the oil reserves suggest that by the year 2015 we will have used all of our accessible oil supply.”

Yet the Earth still has oil: at least 1.6 trillion gallons of proven reserves, according to the Energy Information Administration, a US government agency. In fact, proven reserves have more than doubled over the last couple decades, as technological innovation made more oil accessible.

The guide is on the website of the Pennsylvania Department of Environmental Protection. Department spokesman Eric Shirk told FoxNews.com that the prediction was “obviously wrong” but added that the guide mostly consists of practical information on how to recycle oil that is still current.

4) Arctic sea ice will disappear by 2015.

“Peter Wadhams, who heads the Polar Ocean Physics Group at the University of Cambridge… believes that the Arctic is likely to become ice-free before 2020 and possibly as early as 2015,” Yale Environment 360 reported in 2012.

Yet government data shows that arctic sea ice has increased since then. At its lowest point during 2014, sea ice covered about 1.7 million square miles -- an area nearly half the size of the United States.

Wadhams did not respond to a request for comment Wednesday morning.

Update: Wadhams responded Friday and said he stands by his prediction that Arctic ice will have disappeared between 2015 and 2020.

“The observed trend of ice volume in the summer Arctic is strongly negative, and leads to a high probability that there will be an ice-free September by or before 2020,” he said, adding that the recent increase would likely be temporary.

“The volume is subject to random weather-based fluctuations which may cause a temporary rally, as has happened in 2013 and 2014."

5) Looking to the future: A billion people could die from climate change by 2020

Dr. John Holdren, who currently serves as the White House Director of the Office of Science and Technology Policy, made dire predictions about global warming in the 1980s.

Paul Ehrlich cites Holdren in his 1987 book “The Machinery of Nature”, noting that: “As University of California physicist John Holdren has said, it is possible that carbon dioxide climate-induced famines could kill as many as a billion people before the year 2020.”

Holdren told FoxNews.com that he does not view that as a prediction.

“As accurately reflected in the quoted passage, my statement in the 1980s about potential impacts of climate change on food production by 2020 was not a ‘prediction’ or a ‘forecast.’ It was, precisely, a statement about what ‘is possible,’ ” he wrote in an email to FoxNews.com.

There are also still five more years left for the scenario to occur.

“It is a bit too soon, on the eve of 2015, to make any firm pronouncements about what will or will not happen by 2020,” Holdren wrote.

He added that new regulations are the best way to avoid catastrophe.

“I very much hope, of course, that nothing as dire as a famine killing a billion people will happen as a result of climate change by 2020, or ever. But the prospects for permanently avoiding such an outcome… will be greatly improved if this country follows through on the sensible measures in the President's Climate Action Plan,” he wrote.

The author, Maxim Lott, can be reached on Facebook or at maxim.lott@foxnews.com.