When it comes to global warming, extreme scare stories abound. Al Gore, for example, famously claimed that a whopping six metres of sea-level rise would flood major cities around the world.

Gore's scientific adviser, Jim Hansen from Nasa, has even topped his protege. Hansen suggests that there will eventually be sea-level rises of 24 metres, with a six-metre rise happening just this century. Little wonder that fellow environmentalist Bill McKibben states that "we are engaging in a reckless drive-by drowning of much of the rest of the planet and much of the rest of creation."

Given all the warnings, here is a slightly inconvenient truth: over the past two years, the global sea level hasn't increased. It has slightly decreased. Since 1992, satellites orbiting the planet have measured the global sea level every 10 days with an amazing degree of accuracy – 3-4mm. For two years, sea levels have declined. (All of the data are available at sealevel.colorado.edu.)

This doesn't mean that global warming is not true. As we emit more CO2, over time the temperature will moderately increase, causing the sea to warm and expand somewhat. Thus, the sea-level rise is expected to pick up again. This is what the UN climate panel is telling us; the best models indicate a sea-level rise over this century of 18 to 59 centimeters (7-24 inches), with the typical estimate at 30cm. This is not terrifying or even particularly scary – 30cm is how much the sea rose over the last 150 years.

Simply put, we're being force-fed vastly over-hyped scare stories. Proclaiming six meters of sea-level rise over this century contradicts thousands of UN scientists, and requires the sea-level rise to accelerate roughly 40-fold from today. Imagine how climate alarmists would play up the story if we actually saw an increase in the sea-level rise.

Increasingly, alarmists claim that we should not be allowed to hear such facts. In June, Hansen proclaimed that people who spread "disinformation" about global warming – CEOs, politicians, in fact anyone who doesn't follow Hansen's narrow definition of the "truth" – should literally be tried for crimes against humanity.

It is depressing to see a scientist – even a highly politicised one – calling for a latter-day inquisition. Such a blatant attempt to curtail scientific inquiry and stifle free speech seems inexcusable.

But it is perhaps also a symptom of a broader problem. It is hard to keep up the climate panic as reality diverges from the alarmist predictions more than ever before: the global temperature has not risen over the past 10 years, it has declined precipitously in the last year and a half, and studies show that it might not rise again before the middle of the next decade. With a global recession looming and high oil and food prices undermining the living standards of the western middle class, it is becoming ever harder to sell the high-cost, inefficient Kyoto-style solution of drastic carbon cuts.

A much sounder approach than Kyoto and its successor would be to invest more in research and development of zero-carbon energy technologies – a cheaper, more effective way to truly solve the climate problem.

Hansen is not alone in trying to blame others for his message's becoming harder to sell. Canada's top environmentalist, David Suzuki, stated earlier this year that politicians "complicit in climate change" should be thrown in jail. Campaigner Mark Lynas envisions Nuremberg-style "international criminal tribunals" against those who dare to challenge the climate dogma. Clearly, this column places me at risk of incarceration by Hansen & Co.

But the globe's real problem is not a series of inconvenient facts. It is that we have blocked out sensible solutions through an alarmist panic, leading to bad policies.

Consider one of the most significant steps taken to respond to climate change. Adopted because of the climate panic, biofuels were supposed to reduce CO2 emissions. Hansen described them as part of a "brighter future for the planet." But using biofuels to combat climate change must rate as one of the poorest global "solutions" to any great challenge in recent times.

Biofuels essentially take food from mouths and puts it into cars. The grain required to fill the tank of an SUV with ethanol is enough to feed one African for a year. Thirty percent of this year's corn production in the United States will be burned up on America's highways. This has been possible only through subsidies that globally will total $15bn this year alone.

Because increased demand for biofuels leads to cutting down carbon-rich forests, a 2008 Science study showed that the net effect of using them is not to cut CO2 emissions, but to double them. The rush towards biofuels has also strongly contributed to rising food prices, which have tipped another roughly 30 million people into starvation.

Because of climate panic, our attempts to mitigate climate change have provoked an unmitigated disaster. We will waste hundreds of billions of dollars, worsen global warming, and dramatically increase starvation.

We have to stop being scared silly, stop pursuing stupid policies, and start investing in smart long-term R&D. Accusations of "crimes against humanity" must cease. Indeed, the real offense is the alarmism that closes minds to the best ways to respond to climate change.

Copyright: Project Syndicate, 2008.