Climate at a Glance: Ocean Currents

The great ocean conveyor moves water around the globe. Cold, salty water is dense and sinks to the bottom of the ocean while warm water is less dense and remains on the surface. Image: NOAA

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Key Takeaways:

  • For many years, global warming activists claimed climate change would soon cause ocean currents to slow to a pace that has not been experienced in more than 1,000 years.
  • Climate activists claimed computer models predicted the slowdown and that a slowdown would cause disastrous consequences on marine life.
  • They also suggested it could cause a new “mini” ice age.
  • However, recent peer-reviewed research has falsified these claims. The best-available science shows ocean currents have sped up over the past 20 years, not slowed down.

Short Summary:

Ocean currents distribute heat across the globe. The great ocean conveyor moves water in a wellknown
pattern, as seen in Figure 1.1

For many years, some scientists and climate activists have claimed the world’s ocean currents are slowing down and that global warming is to blame. They have cited computer model simulations that predicted and replicated a slowdown.2 Slower ocean currents, they claimed, would alter African and Indian rainfall patterns and impact Atlantic hurricanes. Additionally, in 2019, op-eds and studies claimed ocean currents had declined to their slowest pace in 1,600 years.3,4

However, recent scientific research, relying on real-world measurements, shows ocean currents likely sped up during the same periods that climate activists asserted global warming had started to cause ocean currents to slow.5 It seems that scientists cannot agree on whether ocean currents are speeding up or slowing down. Either way, the media wants you to believe that human activity is the cause of the change, rather than natural variations in Earth’s climate system. Global warming activists cannot have it both ways. Ocean currents could not have been both slowing down to record
lows during the past 20 years while also speeding up.

When climate change activists thought ocean currents were slowing down, they told the public this development would be disastrous and that their computer models predicted this would undoubtedly happen due to global warming. Now that we know ocean currents have been speeding up, many of the same activists tellus this change is also disastrous, and that their computer models predicted accelerating ocean currents all along.6

It is clear global warming activists are continuously altering their claimed “climate crisis” to fit the evolving scientific evidence, rather than simply admitting the obvious: Earth’s climate and ocean currents are always changing and always will, due mostly to natural causes.

Figure 1. Ocean Currents Around the World

Figure1. This figure illustrates how ocean currents affect heat distribution around the world. Source:
National Ocean Service, “What Is the Global Ocean Conveyor Belt?,” National Oceanic and
Atmospheric Administration, last updated February 26, 2021,


  1. National Ocean Service, “What Is the Global Ocean Conveyor Belt?,” National Oceanic
    and Atmospheric Administration, last updated February 26, 2021, https://oceanservice.
  2. Nancy Bazilchuk, “In Deep Water: Will Essential Ocean Currents be Altered by Climate
    Change?,” Scientific American, December 10, 2009, https://www.scientificamerican.
  3. Aylin Woodward, “The Film ‘The Day After Tomorrow’ Foretold a Real and Troubling
    Trend: The Ocean’s Water-Circulation System Is Weakening,” Business Insider, March
    25, 2019,
  4. David Thronalley et al., “Anomalously Weak Labrador Sea Convection and Atlantic
    Overturning During the Past 150 Years,” Nature, Volume 556, April 2018, https://
  5. Shijian Hu et al., “Deep-Reaching Acceleration of Global Mean Ocean Circulation Over
    the Past Two Decades,” Science Advances, Volume 6, No. 6, February 2020, https://
  6. Stephanie Pappas, “Ocean Currents Are Getting Faster,” Live Science, February 6, 2020,

Climate At A Glance is a Project of The Heartland Institute