During the last several weeks, Thomas Piketty’s magisterial Capital in the Twenty-First Century has earned great protestation on the heels of great praise. As the hits keep coming, I am reminded of the experience of another courageous, insightful truth-teller: Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change, whose work the Rockefeller Foundation supported when I served there for much of the 2000s.

Many will remember that Pachauri and the IPCC shared the 2007 Nobel Peace Prize with former US vice president Al Gore. Earlier that year, the panel’s so-called Fourth Assessment Report was the very first to demonstrate “unequivocally,” in its phrasing, that human activity is warming our world with worsening consequences.

And yet, by 2010 a number of pundits had taken to the talk shows and opinion pages—from the Financial Times to the New York Times—calling for his resignation.

What was Pachauri’s impeachable offense? After countless false recriminations and abundant sound and fury, there were two quibbles of merit. Among the more than 18,000 references cited in the IPCC’s 2,800-page assessment, one overestimated the speed at which Himalayan glaciers are melting (for which the IPCC later apologized) and another included a typo in the percentage of the Netherlands that lies beneath sea level. From there, the “climate-gate” juggernaut had all the fuel it needed to drive lingering doubt about climate change into our political consciousness and public conversation.

It’s understood that translating data into meaningful insights requires a number of interpretative decisions, to say nothing of rigorous peer review. No one pretends that these interpretive choices of data handling are without some subjectivity. What matters with data-driven scholarship like Pachauri’s and now Piketty’s is how transparent the scholar’s choices are, and how fair and defensible the resulting conclusions.

This is why it is worth noting that when Piketty responded directly to criticisms in the Financial Times a few weeks ago, he expressed openness about his choices, honesty about the certainties and shortcomings of his conclusions, and fidelity to a full and free exchange of ideas. In this regard, Pachauri and Piketty are scholarly kindred spirits.

What worries me is not the existence of debate about Pachauri’s or Piketty’s research. What worries me is the willful insistence that something must be wrong with the data because critics don’t like the conclusions of the researcher.

In other words, what worries me is an intense feeling of déjà vu all over again.

For years, climate-change deniers—many of them supported by powerful interests—ginned up false controversy in order to erode the credibility of climatology. Following the tobacco industry’s tried and true tactics of the 1970s, a climate-crisis-denial industrial complex sowed skepticism to distract from, and ultimately derail, important conversations about solutions.

As a result, we have lost years of opportunity. We are a decade nearer to environmental and human catastrophe, but hardly any closer to a response befitting the scale of the crisis.

I would like to think that a similar pattern of discrediting and delay could not unfold again. I would like to think that our lived experience with widening disparity—reinforced by clear and compelling data—will keep inequality-denial at bay.

But what troubles me most about the FT’s approach to its Piketty critique is not that the paper raked through the data sets. That’s fair enough. It’s the implicit assertion—assuming Picketty is wrong and inequality is marginally less severe today than it was during the Industrial Revolution—that beating a 200-year-old standard of inequality is a major accomplishment that we should feel good about.

As president of a foundation dedicated to advancing fairness, opportunity and rights, I am regularly disheartened by the ingenious and insidious methods by which the well-being and aspirations of ordinary people are undermined by those with power. Far from being persuaded by the arguments of inequality deniers, the message I take away is that we remain tragically far from where we should be in fulfilling the universal human yearning for justice and dignity.

Given that inequality and climate change are two of the most significant challenges to humanity in this century, it is critical we see the debates surrounding them for what they truly are: enormous struggles over power and possibility. It is up to of us to snap out of the déjà vu, recognize we have been here before, and change course.