The BOM outlook for the weather over the next three months is ‘neutral’ – here’s what that really means



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It’s more important to know whether there’ll be any weather than what the weather will be.
Photo by Loren Gu on Unsplash, CC BY-SA

Andrew B. Watkins, Australian Bureau of Meteorology and Felicity Gamble, Australian Bureau of Meteorology

Today the Bureau of Meteorology releases its end-of-month seasonal outlook for April to June, updating the initial outlook released on March 15. But you might not have seen much media coverage of it, because we’re not seeing big swings towards the attention-grabbing climate drivers like El Niño or the Indian Ocean Dipole, which can dominate Australia’s climate.




Read more:
Dipole: the ‘Indian Niño’ that has brought devastating drought to East Africa


There are times when the main drivers of our climate are not strong enough to push us towards a season dominated by unusually wet or dry, or hot or cool, weather. This can also happen if different climate drivers are having opposite impacts – they can cancel each other out.

Without a strong push one way or another, our outlook maps are often white. This is a neutral or “50:50” outlook map.

The rainfall outlook map for April–June 2018, issued March 15 (left), shows most of Australia in the neutral/50:50 range (so coloured white). In contrast, the rainfall outlook map for October 2015 (right) shows a low chance of exceeding the median (so brown dominates the map).
Bureau of Metereology

A 50:50 outlook map doesn’t mean we’re taking a guess, or that there’s no indication of what’s happening with our weather and climate. In fact, it’s giving us some key information.

What does a neutral outlook mean?

Let’s focus on rain. A neutral climate outlook means there is a 50% chance of above-average rainfall. In other words, there is an equal chance of getting above-average or below-average rain over the coming season.

But it doesn’t mean that the most likely rainfall is spot-on average. Have a look at the graph below for rainfall in the Murray—Darling Basin. It shows rainfall over 116 years, ordered from lowest to highest. Years with no strong climate driver, or no strong push from the climate system one way or another, are in blue.


Bureau of Meteorology

Most winter–spring periods (29 out of the 40 years, or about three-quarters of all years) fall within the middle 50% of past rainfall totals, as indicated by the 25th and 75th percentile lines. But within that middle 50%, the rainfall in neutral years is fairly evenly spread — it isn’t clustered right in the middle, or dead on average.

This means two things.

First, it means that a neutral year will typically bring quite variable rainfall, with periods of rainfall above or below average. We also know that the above or below patterns tend not to be as widespread across the continent as during stronger La Niña or El Niño periods.

Second – and importantly – it also means there is less chance of extremely wet or extremely dry conditions over large areas; that’s a good sign if drought or flood is a concern.

What doesn’t a neutral outlook mean?

A neutral outlook certainly doesn’t mean climatologists are having a bet each way. We can think about this in terms of a football game.

Some footy games we are fairly sure will be a one-sided affair — based on previous match performance, players’ injuries, whether it’s a home or away game, and so on. On other occasions, those factors aren’t in play and the teams are very evenly matched, so the result could go either way. It doesn’t mean we don’t know much about footy or about the teams that are about to play – it’s just that there is no strong indication that one team is far better than the other.




Read more:
A chaotic beast, probably: wacky weather and climate forecasting


What can I do with a neutral outlook?

So what should you look at during neutral periods to get an idea of what’s possible for the upcoming season? Well, there’s lots of additional information on our climate outlooks website.

For a start, think about your local rainfall at a particular time of year, and what range you typically have in years without flood or drought. Use our rainfall ranges information to see your current rainfall accumulation, and what result you’ll get in a few months’ time if a typical range (wet, dry or average) of rain falls over the season.

The seasonal outlook itself may also be useful. For example, if you need a certain amount of rainfall, say 100mm over the next season, you can check out the likelihood of that happening. Or looking at it the other way round, what rainfall amount has a 25% (less likely) or 75% (more likely) chance of occurring, as shown below.

BOM seasonal outlook.

Other tools worth worth looking at in neutral periods include streamflow forecasts, which can tell you if streamflows are likely to be high, low or average in your region, and soil moisture guidance, to assess your soil moisture for daily and monthly periods.

And, of course, you can find the typical rainfall range for your area in our Climate Data Online. Select “Weather and Climate” at the top and “Monthly” statistics.

BOM Climate Data Online.

All of us – including climatologists – wish the outlooks were always clearly wet or dry, or hot or cool. It would certainly make all our lives a lot easier! But when the climate drivers are not strong, or oppose each other, there’s rarely any chance of a big push towards one outcome – and that information is still useful for making decisions.

A neutral outlook indicates a 50% chance of above-average rainfall. This means there is more chance of good rain than in a season with only 25% probability, but less chance than a season with 75%.

If your appetite for risk is high – if you are a farmer with good soil moisture, full dams and lots of money in the bank – 50% may be enough for you to take a punt on a riskier crop. But if times are tough, 50% may not be anywhere near high enough, so you’d make a more conservative decision. No number is ever too small if the return is high enough: most of us have bought a lottery ticket even though the odds might be one in a million.




Read more:
Curious Kids: What causes windy weather?


At the end of the day, a 50% chance is a number just like any other. When combined with your knowledge of what a typical range of outcomes may be, other bureau information at your fingertips, and your appetite for risk, it can still help you make a climate-smart decision.


You can stay on top of what’s happening with the climate by subscribing to the Bureau of Meteorology’s Climate Outlooks.

The ConversationThis is an edited version of a post that appeared on the Bureau of Meteorology’s blog.

Andrew B. Watkins, Manager of Long-range Forecast Services, Australian Bureau of Meteorology and Felicity Gamble, Senior climatologist, Australian Bureau of Meteorology, Australian Bureau of Meteorology

This article was originally published on The Conversation. Read the original article.

Sustainable shopping: save the world, one chocolate at a time


Robert Edis, Australian Centre for International Agricultural Research; Kanika Singh, University of Sydney, and Richard Markham, Australian Centre for International Agricultural Research

Shopping can be confusing at the best of times, and trying to find environmentally friendly options makes it even more difficult. Our Sustainable Shopping series asks experts to provide easy eco-friendly guides to purchases big and small. Send us your suggestions for future articles here.


Cocoa is probably the most sustainable of all internationally traded commodities, so there are several “feelgood” reasons for eating the chocolate made from it this Easter – at least when the cocoa is grown by smallholder producers and traded by processors that are committed to equitable sharing of profits.

Here are some ways to tell if you are onto a good thing.

Environmental impact

As a wild species, cocoa (Theobroma cacao) originates from the rainforest of the Amazon basin and the foothills of the Andes. In nature, it grows as an “understorey” species, shaded by the rainforest canopy. Much of the world’s cocoa crop is similarly grown in the shade of taller trees in mixed plantings.

Unlike many plantation crops, like rubber and oil palm, cocoa can be grown with a diverse mixture of other plants. Of course, not all growers produce this way, so if preserving biodiversity is a priority for you, look for Rainforest Alliance certification.

Healthy cocoa, grown in an agroforestry system with minimal chemical inputs, in Fiji. The cocoa beans are in the yellow pods.
Richard Markham

Cocoa needs a lot of water to survive, so large irrigated plantations have a high water footprint. On the other hand, almost all smallholder cocoa is grown without irrigation in high-rainfall areas, so the water used in production of the cocoa is close to zero (apart from a small amount of water used in processing).

Another environmental aspect is the use of fertilisers and pesticides. When cocoa pods are harvested they take a lot of nutrients with them, out of the ecosystem. On average, a kilogram of dry cocoa contains 36 grams of nitrogen, 6g of phosphorus, 72g of potassium, 7g of calcium, and 6g of magnesium.

This means maintaining soil condition is critical. This can be achieved with careful application of fertiliser, though this rarely occurs and soil depletion has become a major problem prompting aid groups to encourage more fertiliser use!.

However, research in Sulawesi, supported by the Australian Centre for International Agricultural Research and chocolate giant Mars Inc, has shown that using a judicious combination of nitrogen-fixing shade trees and compost (ideally produced with the help of goats) can maintain soil fertility – and even reclaim depleted speargrass savanna – for cocoa production.

Trials by Indonesian and Australian researchers in Sulawesi suggested that a combination of compost and inorganic fertiliser gave the best results.
Richard Markham
Research trials on sustainable cocoa production at the ‘Mars Academy’ research station in Sulawesi, Indonesia.
Richard Markham

Finding good chocolate

The good news is that there are plenty of chocolate producers who avoid all of these problems. There are two ways to find it: look for certifications, or seek out small operations in our region.

Fairtrade certification means that smallholder producers in developing countries are getting a fair share of the price you pay.

Rainforest Alliance certification, meanwhile, ensures that rainforest hasn’t been cleared to make way for unsustainable plantations.

If you’re concerned about fertiliser and pesticide use, UTZ (who have recently merged with the Rainforest Alliance) has built sustainable productivity into their certification systems.

All of these certification schemes are largely available to multinational companies. Some of the biggest chocolate companies in the world, including Mars, Ferrero, Hershey and Nestlé, have committed to sourcing 100% certified cocoa, so it’s possible to buy sustainable cocoa without even realising it.

On the other end of the scale are smallholdings, which are likely to lack these kinds of certifications. That doesn’t always mean they are bad for the environment, or that the growers aren’t getting a fair price. It may simply be that the expense of formal certification is not worth it for many small operations.

Much of this chocolate is organic more or less by default, as many smallholders, especially in the Pacific region, simply do not use agrochemicals. It’s also more likely to be grown in heavily rainforested areas, with almost zero water footprint.

In their search for high quality and unique flavours, several Australian boutique chocolate makers have started to source their beans directly from cacao growers.

For instance, Bahen & Co. in Margaret River, Western Australia, purchases beans directly from communities on Vanuatu’s Malekula island, while Jasper & Myrtle in Canberra buys beans from growers on PNG’s previously troubled island of Bougainville.

These programs mean that these growers have been able to taste chocolate from their own beans for the first time, and thus understand how their own processing of the beans – through fermentation and drying – affects the quality of the final product.

Australian chocolate maker Mark Bahen evaluates samples of beans from individual growers in Vanuatu.
Conor Ashleigh for ACIAR

Even more value can remain with the local growers and their communities if the chocolate itself is manufactured in-country. Visitors passing through duty free shops as they leave PNG may have picked up Queen Emma chocolate, made by Paradise Foods in Port Moresby, while those leaving Nadi may have bought Fijiana chocolate made by local company Adi’s Chocolate.

Australian shoppers will soon be able to buy Aelan chocolate – single-origin bars from four different islands of Vanuatu, made in Port Vila by ACTIV, a Victorian NGO founded and operated on fair-trade principles.

At the furthest end of the fine-flavour chocolate trend are chocolate bars with no artificial additives of any kind. A favourite recipe among discerning chocolate-tasters is simply to mix 80% cocoa “nibs” (coarsely ground beans) with 20% sugar and “conch” it gently until smooth and delicious.

Drying cocoa beans in the sun helps to develop the best flavour (in this case Kerevat, PNG)
Yan Dicbalis

What about food miles and the carbon footprint?

The typical cocoa bean from the Asia-Pacific region is bought by the local representative of a global commodity trader. It is shipped to Singapore, or directly to Indonesia, which has the capacity to grind some 600,000 tonnes of cocoa each year. The ground or whole beans then travel onward to Europe.

Belgium has a well-established reputation as the world’s preferred provider of “cocoa liquor”, and some of this is shipped back to Australia as the raw material for local chocolate manufacture – now with a sizeable carbon footprint.

Other beans will be shipped to France, Italy, Switzerland (or will remain in Belgium) for manufacture into delicious chocolates, and some of these too will be shipped back to our region for retail sale. If fossil fuels and global warming are among your concerns, consider seeking a chocolate product that was grown and processed nearby.

The big players are Cote d’Ivoire, Ghana and Indonesia, with small amounts of smallholder-dominated production in the Pacific.
ICCO, 2017. Quarterly Bulletin of Cocoa Statistics. Vol. XLIII, No. 3. Cocoa year 2016/17. International Cocoa Organization, London

The ConversationIn sum, with a bit of attention to the back story, you can enjoy a whole range of delicious new chocolate experiences this Easter – and feel that you are contributing at the same time to the equitable and sustainable development of the planet.

Robert Edis, Soil Scientist, Australian Centre for International Agricultural Research; Kanika Singh, Research Fellow, University of Sydney, and Richard Markham, Research Program Manager for Horticulture, Australian Centre for International Agricultural Research

This article was originally published on The Conversation. Read the original article.