Despite the rain pouring down outside my window right now and the fact I am wearing a jumper in late June, I can’t actually see climate change. I can go to the co2.earth webpage and learn that the latest figures for Co2 in the Earth’s atmosphere, as measured at the Mauna Loa station in Hawaii, are 409.65ppm. But what does that mean? What does it feel like? Should I be worried that in March this year it was 407.05ppm? That in March last year it was 404.86ppm, and the year before 401.51? The numbers are clearly going up. But does it feel any different?

A couple of days ago, as I was wondering what to write about this week, I saw the headline: “World has 3 years to save humanity from climate change, experts warn”. I kept wondering what to write about. But try as I might to find other elephants tucked under the sofa, I just couldn’t get past this one.

But where to begin with a topic that is so hard to talk about? It’s not as if we lack for content ideas. There’s the recent story about the aviation industry’s proposed solution to its carbon emissions, one that relies exclusively on offsetting to enable “carbon neutral growth”. Unfortunately, a study by the European Commission published a few weeks ago found that 85% of the offset projects used failed to reduce emissions.

Or there’s another story, also from the EU, which reported that greenhouse gas emissions from transport grew by 28% between 1990 and 2015, while over the same period household emissions dropped by 25% and industry’s fell 37%. However, as the study made clear, not all transport types saw their emissions rise. “Emissions from rail transport account for 0.1% of total EU emissions and decreased by 54% between 1990 and 2015,” reported the International Railway Journal.

There was also a recent comment piece on the Devex platform, where the UN’s Taleb Rifai, Erik Solheim and Patricia Espinosa talked about tourism and CO2 and wrote: “Tourism generates an estimated 5 percent of global greenhouse gas emissions. According to U.N. Environment, that proportion is higher — 12.5 percent — if factors such as energy use at hotels and transporting food and toiletries are included.”

So which is it? 5% or 12.5%? It has to be the higher figure. I can think of no good reason why a hotel’s supply chain choices and energy use would not be factored into the emissions for which it was considered responsible.

In the very next line they write: “Other sobering figures include water use. A tourist in Europe will consume more water on holiday than at home.” Although they don’t say it directly, such water use will have also added to climate change emissions, even though these were probably not accounted for either. Unless the water fell from a waterfall or was scooped by hand from a stream, it took embodied energy to purify, transport and process it into whatever form it is being used by tourism. And then results in emissions.

Talking about climate change is hard, and will remain hard while we struggle to even get our definitions right. There’s nowhere that this is more clearly illustrated than in the use of the word “emissions” itself.

More often than not when companies say emissions what they really mean is “emission intensity”. Read any number of press releases or websites and you will see companies talk about having reduced their emissions by a certain percent, when what they actually mean is they have increased their efficiency.

In a world where business’ central survival policy is to keep growing, this matters. If I have 10 hotels / airplanes, and I make them 10% more energy efficient, then yes, my emissions the following year can be said to have reduced by 10%. But if during the same period I build two more hotels / airplanes, also running at the same efficiency, then my business may be 10% more efficient (in other words have a 10% reduction in emissions intensity), but my total emissions will have risen. The Climate Council reports: “Reducing emission intensity means that less pollution is being created per unit of GDP. But! And this is a big ‘but’ – if GDP grows then so too do total emissions.”

This sort of semantic double play can be seen when companies talk about carbon offsetting. I am all for trees. Trees compensate for our emissions, as they absorb carbon through photosynthesis. We need trees, lots of them.

But if a hotel produces 100 tonnes of emissions, and then buys carbon offsets that are supposed to account for 20 tonnes of emissions, then the hotel’s emissions have not reduced. The hotel is still creating the same amount of climate-altering gases as it was before it purchased the offsets. What it has done is supported someone else, somewhere else, to act. As Chris Lang writes on the Climate and Capitalism website: “There is an equation to illustrate that carbon offsets do not reduce emissions: 1 – 1 = 0. Most people can understand this. If emissions are reduced in one place (-1) but through the sales of carbon credits emissions are allowed to continue somewhere else (+1) the overall result is zero.”

I am not with those who believe that this is an argument against carbon offsets and therefore they should not be part of the conversation. I believe this is an argument against the language used to describe the purchase of and use of carbon offsets.

You may disagree. Get in touch, I welcome a conversation with anyone who wants to talk about climate change and tourism. What I am most concerned with is that this conversation, the biggest conversation there can be, one we were supposed to have been having for over 20 years, remains one we are still struggling even to find the words to engage with.