IPCC’s fifth Assessment Report is Happy Reading

by Robin Grieve- Pastural Farming Climate Research

The television news painted a grim picture when it announced the findings of the IPCC’ fifth assessment report. “Rising sea levels, more extinct species and possible food shortages are the grim prediction” intoned the news reader, her grim seriousness matched by the image of a sad looking polar bear behind her.  “And New Zealand is set to feel the heat too. The capital had its worst storm in 40 years, harsh drought hit the North Island summer and this winter was the warmest on record.”

The direness of our situation called for desperate action and I decided to take it. I decided to read the fifth assessment report for myself. With fourteen chapters all between one and two hundred pages, it was a desperate action.

This report is not written by hundreds of scientists, as they like to say it is. Hundreds of papers are submitted by scientists, which are then referred to in a sort of summary written by others. There are many scientific papers, a number of which are contradictory. Summaries throughout the fourteen chapters try to reach conclusions from the diversity of evidence and often end up contradicting conclusions made in other summaries.  The only consistency in the whole thing being that each summary tries to paint as dark a picture as it can.

The first impression I got however was that, despite the dark spin the writers put on it, there is a lot of good news in the report. These are the parts that the TV news did not report.

Previous predictions about drought in the last assessment report were overstated and the IPCC now say that there is not enough evidence to support an increase in global-scale observed drought.

There continues to be a lack of evidence to support the sign of trend in the magnitude and/or frequency of floods.

There is low confidence in observed trends in small scale weather events. Data indicates no significant observed trends in global tropical cyclone frequency. There is low confidence for a trend in storminess, likewise high winds. In another part of the report they do predict a decrease in storms in both hemispheres with medium certainty in the Southern hemisphere and low certainty for the Northern. 

On the topic of extreme precipitation the report says there are two possible climate mechanisms controlling extreme precipitation amounts. Note the use of the word ‘possible’ which means they don’t really know.

The first suggests that there would be more intense precipitation because a warmer atmosphere held more water vapour and therefore rainfall would be heavier. However an alternative and more favoured model suggested that precipitation intensity was associated with updrafts and not increased water vapour concentration. The effect of temperature increases on the incidence of updrafts is unknown, so if this is the mechanism that controls extreme precipitation intensity then the effect a warming world will have on updrafts and therefore precipitation intensity is unknown.

It is on the predictions they make for New Zealand that the inadequacy of the report is obvious. The models predict there will be rainfall changes in New Zealand of between -10 and +25% by 2090 (compared with 1990).

One would think that faced with different models predicting changes between 10% less rain and 25% more rain they would say that the models are a waste of time. Not the writers for the IPCC however, who are charged with writing a grim report regardless of the evidence and so they predict that we will have heavier precipitation, even though the causes of heavier precipitation, as previously stated, are unknown. Even more ridiculous is their prediction that our indigenous people will be more affected than other New Zealanders because they are more dependant on the land for income than non indigenous people, really? What is worse for our indigenous people, according to the IPCC, is that their land is steeper than non indigenous people’s (I am not joking) and so will suffer more from erosion caused by the heavy rain that other parts of the reports said would not eventuate. I would say it is far more accurate to say that it is not global warming that is affecting our indigenous people; it is our Government’s idiotic response to it. John Key’s ETS impacts far more on the poor and Maori are more highly represented in that demographic. Maybe it is all that steep land they own that puts them there? 

So fear not the dire predictions of our news readers, I don’t think anyone at TV One even read the report because what they said and what was in the report are complete opposites. Yes the IPCC do predict that everything is going to get worse, but with no observed trend of increasing drought or flood or extreme weather events over the last century, despite CO2 levels having already increased and temperatures already almost one degree warmer, you can be sure of two things. The Capital’s worst storm in forty years and the harsh drought of last summer had nothing to do with global warming and secondly, with no trend of weather changes established, predictions of how bad things are going to get can quite safely be taken with a grain of salt.