A Cleantech VC Who is Unconvinced of Man-Made Climate Change


Go ahead — call me a hypocrite. I claim to be a cleantech venture capitalist yet I tell you here and now that I am not convinced of anthropogenic (human-caused) climate change (aka global warming). And I will audaciously tell you that my convictions on climate change in no way run contrary to my strong belief in the need for a cleantech revolution.

Many supporters of clean technologies make it seem as though anthropogenic climate change is an absolute fact. To some of them anthropogenic climate change is almost like a religion where any debate or doubt is not tolerated. Some of them may call me a heretic just for writing this post.

At the same time, those on the other end of the spectrum are equally religious in their fervor and certainty that anthropogenic global warming is a fraud. They are certain that human emissions of carbon dioxide and other “greenhouse” gases could never impact our climate. And they may twist this post to use it as yet another data point against claims of global warming and added rationale to do nothing except increase fossil fuel exploration.

In both groups, it is my perception that most have read little about the topic other than the popular press. And I find both groups equally sad in their myopic viewpoints. If both of these camps would open their eyes, I suspect there would be much greater agreement on the need for action on clean technologies rather than the divisiveness that their polarizing views create.

There are solid scientific theories and extensive data, anchored by the UN Intergovernmental Panel on Climate Change Report, that indicate the possibility that over time man-made emissions of greenhouse gases could impact the global climate and may have already begun to do so. To dismiss them out of hand because there is some reasonable doubt is irrational.

Similarly, to speak about anthropogenic climate change as a certainty or to claim that there is no disagreement among scientist is simply incorrect. There are large numbers of reputable climate scientists who remain unconvinced. The reality is that all predictions of global warming are based on very complex climate models. We can forecast the weather a few days out with reasonable accuracy but if you try predicting next year’s summer temperature — let alone long-term global climate conditions — things fall apart quickly. Long-term climate models are anything but accurate.

We know with certainty that past natural occurrences have caused significant changes to the atmosphere, resulting in climate changes. So, there is little question about whether changes in the atmosphere can cause climate changes. Rather, the question is whether man-made emissions are significant enough to cause a change on their own and to overcome the large natural forces on our climate that include sun spots, variations in the earth’s orbit, and volcanoes all of which have not been taken into account in forecasts of global warming.

Often there is a focus in the media on recent variations in climate as a source of evidence for anthropogenic climate change. Variations in climate over short periods of time are highly suspect as evidence. While most scientists seem to agree that there have been increased temperatures and other climate changes over the past century or so, what cannot be said with certainty is that the increased CO2 levels caused this as opposed natural climate change events that have and continue to happen regularly to our planet. Even the UN Intergovernmental Panel on Climate Change report, which is the backbone of support for anthropogenic climate change, found that its confidence in human contribution to such measured weather events (e.g., temperature, severe storms, sea level, etc.) could be as low as 50% for most of the events and 66% for the others (pages 23 and 52 of the Technical Summary).

Climate change is measured over extremely long periods of time – not a few years or tens of years. Some of the best long-term data on historic CO2 concentrations and temperatures is derived from glacial ice core data that spans back 400,000 years. This data shows that the concentration levels of CO2 in the atmosphere today are strikingly more than 20% higher than any level measured in the past 400,000 years (See Figure 1). The recent rapid increase corresponds well with the industrial age and temperature variations are in high correlation with CO2 concentrations. This is hard data to ignore or simply write-off.

Figure 1 – Data from Vostok Ice Core (400,000 years)

Figure 2 –Estimated CO2 and Temperature Changes over 500+ Million Years

But interestingly over longer periods, the level of CO2 today is far below the estimated levels during many times in history (Figure 2) raising the possibility that the current spike may have other natural contributors. And the correlation between temperature and CO2 that seems so apparent in the 400,000-year ice core data becomes much less clear when looking over many millions of years.

While most scientists seem to believe that, in isolation, increased CO2 concentrations create an increased “greenhouse” effect whereby the CO2 acts like a blanket, preventing more of the heat radiated by the earth from going back into space, at what concentration level and over what time period remains a point of uncertainty and debate. In addition, how other factors that may occur with warming such as increased moisture and clouds as well as changes in absorption of CO2 into the ocean at varying temperatures will affect the warming dynamic and other climate change is much more uncertain.

The bottom line is that we won’t truly know if man has caused climate change until after it has already occurred for a very long period of time.

And that’s the rub. The theoretical costs to the human race of global warming are high: rising ocean levels, decreased polar ice, increased severe weather and significant changes in precipitation patterns. If they occurred to a significant degree, all could have sizeable economic and health implications. But there is no certainty that we will ever pay such a price. More compelling is what we know with near-certainty:

· Fossil fuels are a finite resource and they do pollute. Reduction of pollution is always a good thing. And with booming energy demand in China and India, fossil fuels are a resource that will become scarcer and more expensive. You can argue about the pace, but few argue that it will happen. Even oil rich countries such as Saudi Arabia have begun to accept this fact.

· Increased sources of cost-effective energy and more energy-efficient consumption have and will continue to lead to increased standards of living.

· Nations with greater diversity of energy sources have greater economic and national security.

· The U.S. Defense Department believes that climate change will impact our national security.

· If anthropogenic global warming is real, by the time we start paying the price for the damage we have done it will be too late to turn things back quickly.

To claim with certainty that man is causing climate change or to claim there is no risk of anthropogenic climate change are equally incorrect and equally polarizing.

While it is not certain, there is evidence that suggests that human emissions of greenhouse gases may be changing our climate in ways that could have dramatic impacts. We can do nothing and roll the dice that everything can be OK. Or we can take steps to diversify our energy sources away from fossil fuels and increase our energy efficiency, thereby not only reducing the risk of anthropogenic climate change but also increasing the robustness of our economy and our national defense.

Although there should be debate about the specifics of how to best advance the availability and utilization of cleaner technologies, support for cleantech innovation should be the ultimate bipartisan issue without the divisiveness created by talking about anthropogenic climate change as if it is a fact or as if it is fiction.

David Gold heads up cleantech investments for Access Venture Partners. He is also the author of the GreenGoldBlog.

About Author

Walter’s contributions to CleanTechies over the past 4 years have been instrumental in growing the publications social media channels via his ongoing editorial and data driven strategies. He is the founder and managing director of Sunflower Tax, a renewable energy tax and finance consultancy based in San Diego, California. Active in the San Diego clean technology community, participating in events sponsored by CleanTech San Diego, EcoTopics, and Cleantech Open San Diego, Walter has also been a presenter at numerous California Center for Sustainability (CCSE) programs. He currently serves as an adjunct professor at the University of San Diego School of Law where he teaches a course on energy taxation and policy.


  1. Steven Hickcox on

    Someone please remove this hack piece. David Gold is a Global Warming denier who has a plethora of similar hack pieces in the blogosphere, dismissing the science.

    • Steven,

      I couldn’t ask for any better marketing for my post than a comment like yours. It was comments like this and analogous ones on the other side from those in the “drill baby drill” crowd that prompted me to write this post in the first place. It reinforces my main point about the polarization that is created by folks on both of the far extremes of this issue who will simply dismiss and attack anyone who is less than certain that man-made global warming exits or (on the other side) does not exist.

      Love the way you label me a “Global Warming Denier”. Very inaccurate, but very in line with the religious innuendo I hint at in my post. Hallelujah!

      • Steven Hickcox on

        David, you are not a climate scientist and yet you took this opportunity to try and refute the consensus among bodies of science who study climate, that Global Warming is real and is being accelerated by CO2 emissions. Anyone who has a basic understanding of modern science understands that science is never absolute or certain. However, that doesn’t negate the very real conclusion that human activity is the main culprit in the rising temperature of the earth.

        For you to carry on as if there is even a scientific debate on this is disingenuous at best. By all means, if you believe that someone you’ve figured out what peer-review hasn’t been able to, and you are truly sincere in getting to the truth, you should submit your ideas for scrutiny, but I hunch is you will not. Instead, you’ll use this forum and others in hopes to confuse or misinform readers into further believing that the jury is still out on whether CO2 emissions are contributing to Global Warming. And I’ll be right there to expose your tactics.

      • Steven Hickcox on

        David Gold must have conveniently overlooked these inconvenient facts:

        The Scientific Consensus on Climate Change

        by Naomi Orekes


        “The scientific consensus is clearly expressed in the reports of the Intergovernmental Panel on Climate Change (IPCC). Created in 1988 by the World Meteorological Organization and the United Nations Environmental Programme, IPCC’s purpose is to evaluate the state of climate science as a basis for informed policy action, primarily on the basis of peer-reviewed and published scientific literature. In its most recent assessment, IPCC states unequivocally that the consensus of scientific opinion is that Earth’s climate is being affected by human activities: “Human activities … are modifying the concentration of atmospheric constituents … that absorb or scatter radiant energy. … [M]ost of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations””

        IPCC is not alone in its conclusions. In recent years, all major scientific bodies in the United States whose members’ expertise bears directly on the matter have issued similar statements. For example, the National Academy of Sciences report, Climate Change Science: An Analysis of Some Key Questions, begins: “Greenhouse gases are accumulating in Earth’s atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise.” The report explicitly asks whether the IPCC assessment is a fair summary of professional scientific thinking, and answers yes: “The IPCC’s conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue.”

        Others agree. The American Meteorological Society, the American Geophysical Union, and the American Association for the Advancement of Science (AAAS) all have issued statements in recent years concluding that the evidence for human modification of climate is compelling.

        The drafting of such reports and statements involves many opportunities for comment, criticism, and revision, and it is not likely that they would diverge greatly from the opinions of the societies’ members. Nevertheless, they might downplay legitimate dissenting opinions. That hypothesis was tested by analyzing 928 abstracts, published in refereed scientific journals between 1993 and 2003, and listed in the ISI database with the keywords “climate change”


  2. I sat along the lake watching the waves. Wave, upon wave, moving across the water at varying frequencies, some combining to form larger waves, others reducing the wave effect. So too are the factors involved in climate. Energy flow through the atmosphere, oceans and continents is very complex and dynamic system. Yet as David Gold so clearly writes, fossil fuels pollute. The relative cheapness of fossil fuels has also resulted in inefficient use of energy. Dramatic climate change is happening: “Climate Change May Bring Big Ecosystem Shifts” > and we need to respond in ways that will reduce negative consequences from these changes.

  3. As a very old and retired engineer this article by David Gold will do far more to promote renewable energy that everyone’s global warming rebuttals combined. Negative rebuttals do nothing but cause people to look for a way to fight back when what we really need is more solar, wind, bio-fuels, geothermal, hydro, wave and other forms of renewable energy.

    I once sold solar PV systems. I can tell you from dealing with hundreds of people the bottom line is this – I could sell customers solar PV systems but I could NEVER sell them “global warming”. GLOBAL WARMING is NOT a product or service and global warming believers are hurting themselves and others by continuing to hold on to this outdated term.

    We are SO FAR BEYOND the need for this term. We are already into building large scale construction projects to COMBAT global warming. That to me is where the focus needs to be. The customers I sold solar systems to NEVER said they were buying a system to help reduce “global warming”. In fact, when I did bring up the subject I NEVER GOT THE SALE. What the “people” were interested in was how much is it going to cost and how much can I save.

    There will always be people who believe that global warming is caused by man. There will be others who believe it might be caused by man and still others who believe it is not. That is the nature of society. BUT I can tell you from dealing with many people that most could care less about what the IPCC or some government agency has to say. What most people are sick and tired of is dealing with dirty air, water and high energy prices. People are tired of being cold in the winter and hot in the summer.

    We are years beyond the need to argue about the science [the majority believe it] and NOW it the time to promote the stuff that combats it. After all – isn’t that what we all want?

    • Steven Hickcox on

      Tom, in terms of the science, it isn’t up for debate. To suggest that it is, is doing a disservice to science itself.

  4. Well David:

    Either everyone is hung over from all the New Year’s eve parties or my post killed off all interest in the article.

    I hope everyone is just hung over, LOL