When I was young and single – with no kids and few responsibilities – I loved to sit in the pub with my mates and solve the world’s problems. We enjoyed plenty of discussion of ‘what they should do’ and, after a few tankards of foaming ale, of what each of us would do ‘when they make me king’. Nothing was impossible. We were clear, compassionate, and wise. But at 11 0’clock each night our plans were shut down with the closing of the bar.

In more sober life I saw my role as an environmental scientist to be one of providing information, which could then be used to guide policy. My own studies provided a tiny piece of the puzzle that helped to nail down the source of lead in the environment and in humans: the ubiquitous toxic levels found were dominated by pollution from tetraethyl-lead additives in petrol. Meanwhile colleagues from another section of my institute discovered the Antarctic ozone hole, and correctly attributed it to the prevalence of man-made chlorofluorocarbons (CFCs) in the atmosphere. In a curious quirk of history, these two huge environmental issues are linked by one man, Thomas Midgley Jr., who ‘invented’ both tetraethyl-lead (as a petrol additive) and ‘freon’, the first CFC to be used as a refrigerant. In this respect, Midgley has likely had a larger negative impact on the Earth’s atmosphere than any other organism in history.

Within a few years, national and international agreements were in place to remove lead from petrol, and to replace CFCs with less environmentally harmful compounds. These were solutions that we would have been proud to suggest in the pub. They seemed to indicate a level of sense in both government and business circles that my drinking mates and I had not really credited.

However, the reality was probably somewhat different. The production of tetraethyl-lead and of CFCs were multi-billion dollar industries. But when production of these chemicals ceased, the same chemical companies were the ones that produced the replacements. Cheaply made and highly profitable, the alternatives did not require much in the way of new investment. There was little more than a small hiccough in the flow of profits.

Things are not that simple with climate change – our biggest single environmental problem. For one thing, it is impossible to quantify the value of our greenhouse gas emitting activities in the same way one might evaluate the chemical industry. For example, our use of fossil fuels, the burning of which produces the main greenhouse gas, carbon dioxide, has an impact on virtually every aspect of the economy of every country. Even industries that claim to be clean and green, and sustainably operated are likely to involve use of products made from fossil fuels or use of energy produced from those fuels. Very little truly escapes the influence of coal, oil, and gas. The costs of replacing fossil fuels with other sources of energy is orders of magnitude greater than the replacement of refrigerants and petrol additives. Add to this the uneven distribution of those costs amongst countries and economic sectors, and the difficulty of reaching the necessary international agreements for tackling global climate change quickly grows.

But leaving those costs aside, one of the first problems in reaching any agreement is to demonstrate that climate change is happening at all. The problem starts because we don’t directly experience climate: instead we experience weather. And our experience and memories of weather tend to be subjective.

I remember talking to one friend who, when I told him I was working in climate change research, assured me that his local climate was definitely changing. His example was the depth of snowfalls that occurred intermittently each winter. “When I was a toddler,” he said seriously, “the snow regularly used to come up nearly to my knees. These days, it rarely gets deeper than up to my ankles.” So much for personal experience and memory.

Experience and memories of weather are what we understand, but they are of little use when observing long-term changes. Only measurements and data, correctly collected and recorded, are of use in determining what is happening to climate. But we (as a species) haven’t been collecting data on weather for very long, let alone ensuring it is of high enough quality to be used in climate studies. (Does that new thermometer read exactly the same as the old one we just broke?) Sure, we have a range of ‘proxy’ climate measures – from ice cores, lake and sea-bed sediments, tree rings, and the like – but these tend to be more difficult to interpret than direct measurement. On top of that, there are natural climatic cycles of various lengths, which further confuse the picture. We have not yet identified all these cycles or where we sit within each one. Teasing out what is change and what is cyclical variation is difficult. Separating the natural from the human-induced becomes harder still.

It is little wonder then, that there are still those who argue against blaming global warming on humans, and against any measures to try to do something about greenhouse gas emissions. No matter what weather hits them, they remain climate change deniers.

Which brings me to consider our recent storms. For most of us, data is far less meaningful than direct experience, so meteorologists and scientists have come up with ways of trying to express information about how often we might expect extreme events. On the Coromandel Peninsula, flooding in March of this year was due to a ‘once-in-100-years’ rainfall event. That being the case, why did similar flooding occur in the same place during April: another ‘once-in-100-years’ flood? The terrible flooding in Edgecumbe was supposedly the result of a ‘once-in-500-years’ event. But nobody has lived in Edgecumbe for 500 years to confirm the frequency of such rainfall.

It is statistical analysis that allows scientists to make an estimate of how often flooding might occur. Computer climate models tell us that the frequency of such events will increase as the concentrations of greenhouse gases in the atmosphere increase. Statistical analysis against a changing climatic background becomes more difficult. For insurance companies, this is a real problem, and they are one of the few industries that have genuinely faced the issue of climate change and done something about it: in many cases changing their premium structure and pay-out conditions for weather related events. But for the rest of us, less directly affected, it quickly becomes too difficult to say with any certainty what we need to do to prevent damaging changes. For short-term governments with an eye firmly on the next election, it becomes easier to ignore the problems and to do nothing. As for us voters, even when we worry and care about climate change, we feel useless. Anything we do ourselves will have little effect, so why bother?

And our attention span is short. Last week we heard that the Great Barrier Reef is dying due to pollution and global warming. Cyclone Cook is news this week. Next week Donald Trump will do something else stupid, and the headlines will change again. Oh, and then there’s the school holidays and the kids want to go to the beach one last time before winter …

The reasons we have done nothing, and we do nothing, about climate change are numerous and complicated. So numerous and complicated that I could write a book about it.

In fact, I think it’s time I did.