Her Twitter feed is awash with abuse, detractors dedicate blogs to tearing her down, and there have been attempts to get her fired from her job.
But Professor Katharine Hayhoe, the climate scientist who refuses to stay silent, somehow manages to keep smiling.
It’s a trait that’s part natural disposition and part clever communication strategy. She doesn’t want to fight or instill fear - she wants to engage and encourage action.
She hasn’t much good news to impart but a sunny outlook says all is not lost. Not yet anyway.
Prof Hayhoe travels to Ireland from her Texas base this week for a series of public talks where she’ll be laying on the line the perils that await us if we don’t get climate change under control - while stressing it’s not too late to take action. She’s packing eight talks into five days, beginning at University College Cork tonight before heading to NUI Galway, Queens in Belfast, Trinity College Dublin and Maynooth University.
In university settings she is often preaching to the converted but she’s happy to take on the deniers, doubters and despairing.
It won’t surprise her at all if somewhere along the way she comes up against the view that Ireland is too small to make a difference.
“I have heard that same argument in every single country. I’m from Canada and the number one thing people there say to me is, we’re only 2pc of the problem so we can’t make a difference.
“And in the United States every week I hear people tell me China produces much more than we do so why does it matter what we do?
“But then in China people would say, per person we are one of the least industrialised countries in the world so per person we really have very little effect.
“This same refrain I hear in every single country when the reality is that we all make a difference.
“Our hands are not the only ones on this boulder trying to roll it up the hill. There are hundreds of millions of hands already on that boulder and the more hands we have the faster it moves in the right direction.”
She expects to hear too that climate change debate in Ireland often deepens the urban-rural divide with farmers in particular feeling they’re under attack.
Prof Hayhoe is a devout Christian, the daughter of missionaries who is married to a pastor, and her faith is an important part of what drives her.
Ironically, it’s also among the faith community where she experiences the greatest resistance to her teachings.
“The greatest pushback comes from people I would categorise as political Christians. In the United States, Christianity is primarily associated with politics, not with theology,” she says.
“They view me as a traitor, a heretic, a false prophet. Our greatest hatred is reserved for those we believe are traitors within our ranks.”
In Texas, the oil state, Christian, Republican-voting and conservative, she is never far from someone who views her as a traitor.
The online abuse and scary letter writers she can handle herself - but she feels for her employers at Texas Tech University who have to deal with demands for her dismissal.
Prof Hayhoe came to Texas after an academic career that began with a science degree in physics and astronomy from the University of Toronto.
Climate science became her focus almost by chance, after she took one final semester class in the subject which left her hooked.
Her early research was in climate impact assessments and it remains a core part of her work so that her skills are regularly in demand from cities, farming and energy bodies, public health and water authorities, all scrambling to see what’s likely to happen in their region, locality and areas of responsibility.
She has accolades too many to mention, sits on a multitude of committees and juggles a huge number of public and private projects. Speaking tours became an add-on after she discovered, perhaps because it was in her evangelistic genes, that she was good at it.
Quickly she realised that communicating the science was as important as the science itself, particularly in a field where public buy-in is essential.
She’ll explain that thinking in another of her lectures here: “Talking Climate - why facts alone are not enough”.
“Despite all that we know about climate change, there are still people who believe it’s just a natural cycle, that it’s just something that we have to wait out,” she says.
“Maybe some genuinely believe that but I think many are reacting out of fear which can translate very quickly into anger. The world is changing too quickly and their identities and values are being left behind.
“We often think that to care about climate change, we have to be a certain type of person - a city dweller rather than an urban dweller; a liberal rather than a conservartive.
“The reality is that we all live on this planet. We all need the water that we drink, the resources that we use to make everything that we have.
“My job is to explain that waiting for all this to somehow blow over is not an option. Carbon reduction alone is not even an option. Adaptation is essential too.
“If we continue on our current pathway, we are not going to be able to adapt to the impacts that happen so we need to be doing both.
“We need to be building resilient infrastructure, resilient food and water systems, resilient cities, and at the same time reducing our carbon emissions because if we don’t’, we won’t be able to build a resilient enough economy and country to deal with the consequences.”
Adaptation, she has learned, is less about the physical sciences than the psychological. “In the US, we could cut emissions by 50pc if we were energy efficient - that’s just by changing how we use our energy.
“In most rich countries, we throw out nearly 40pc of the food that we produce and buy. We could make huge emissions savings just by fixing our food use habits.
“We need to get the idea of planetary boundaries clear in our heads. For a long time we have been acting as if our planet had no boundaries. Climate change tells us otherwise.
“There is enough potential for waste reduction to go a long way towards helping us living within our boundaries.
“We need that because we live on a finite planet and we don’t have the time or the resources to terraform Mars before climate change overtakes our civilisation.”
Ideally, world leaders and national governments would be leading their people bravely on the path to universal salvation but the lack of action on the Paris Agreement shows otherwise.
Still, Prof Hayhoe sees hope in actions outside the traditional corridors of power.
“A lot of the leadership is coming below the national level. Cities are really making remarkable forward strides in mitigation and adaptation.
“Some of the world’s leading corporations like Apple, Microsoft, even Walmart have really very strong goals to reduce, eliminate and in some cases, even suck back the carbon emissions they have already produced from the atmosphere.
“In fact, there’s a movement called “we are still in” in the United States and it refers to being still in on the Paris Agreement. The number of cities, states, corporations, universities tribal nations and churches that have signed up amount to almost 50pc of our emissions.
“You never see the headlines about that - you only see headlines about how horrible the federal government is and how terrible the president is and everything they’re doing to roll back environmental protection.
“They are doing that and it is terrible but there is significant hope happening below the national scale and I think that’s really important to emphasise.
“What I’ve found in the United States is that mayors are very pragmatic. They are on the frontlines of the impacts of climate change so they understand the flood risk has increased or hurricanes are getting stronger or heatwaves are more intense and they know that their energy demand is going up but their water supply is going down.
“Whatever part of the political spectrum they’re from, they recognise that they’re being affected and their ability to effect change over their own domain is much greater than that of the president of the United States.
“With corporations, part of them are driven by wanting to do the right thing and part of them are driven by recognising that their stakeholders are actually demanding them to act.
“Part of them are driven by the fact that major investment firms like Blackrock for example, which manages seven trillion dollars around the world, are saying that they are going to be including environmental valuation in their ratings of companies.
“There are multiple factors at work, some of them altruistic, some of them deeply pragmatic but honestly, as a climate scientist, it doesn’t matter why - all it matters is that people are actually doing it.”