Warming will hurt the poor but boost the rich in the short term

Warming will hurt the poor but boost the rich in the short term

Climate change could initially benefit rich countries while damaging the economies of poor nations.

That's the conclusion of a new way of modelling its impact, which challenges earlier forecasts.

Previous methods of estimating the economic effects of climate change usually looked at how individual sectors like agriculture or tourism would be affected, then added them all up to give the net effect on each country's economy.

Such "bottom up" approaches found that climate change would immediately harm all economies, although the impact on rich countries was less marked.

Economist Derek Lemoine from the University of Arizona in Tucson and climate scientist Sarah Kapnick from the US National Oceanic and Atmospheric Administration took a different approach.

They analysed past correlations between countries' economic output and changes in temperature and rainfall, and then used the latest climate models to extrapolate those effects into the future, creating a kind of "top down" picture.

Zero-sum game

They found that with 1 C of warming, the effect on economic growth in the following decade is roughly zero globally. That's because lower growth in poor nations is balanced by higher growth in rich nations.

Beyond that amount of warming, they estimate that economic growth will increase by 1-3 per cent in Europe, North America and Australia, compared with what will happen in a no-warming scenario. But most of Africa, India and parts of South Asia will see a drop in growth by as much as 2 per cent.

Lemoine says the old approach can miss small sectors and assumes there are no interactions between sectors.

The top-down method captures all of that, although it doesn't provide an insight into exactly how climate affects economic performance, because it doesn't break things down by sector.

Lemoine also notes that the model assumes that warming has a linear impact, which is only going to be true for a limited - and unknown - amount of time.

So, he says, rich countries should not treat the model's findings as giving them licence to be complacent over greenhouse emissions.

Bob Ward from the London School of Economics reckons this new approach suffers from the same problems that earlier attempts do: assuming that future warming will affect economies in the same ways as past warming, which ignores the possibility of catastrophic impacts.

"Policy-makers should not use this paper as a guide to the economic risks associated with future climate change," he says.

But Lemoine says the results should help focus our attention on the most relevant costs of near-term warming. These will be borne by poor countries and the environment rather than the rich nations, he says.

And he says that as we get better at defining and modelling economic costs and the likely catastrophic impacts of climate change, they can be added to the tool. "That's exactly our goal," he says.

Journal reference: Nature Climate Change, DOI: 10.1038/nclimate2759

https://www.newscientist.com/article/dn28054-much-of-asias-celestial-mountain-glacier-ice-could-melt-by-2050/

Much of Asia's Celestial mountain glacier ice could melt by 2050

Glaciers are disappearing globally faster than at any time since records began 100 years ago. Most of those in central Asia could be gone by 2050.

The Celestial mountains of central Asia, the Tien Shan range, are thought to be where apples originated. But they have lost 27 per cent of their glacier mass since 1961, thanks to rising summer temperatures, and could lose a further half of what remains by 2050, according to research by Daniel Farinotti of the Swiss Federal Institute for Forest, Snow and Landscape Research in Birmensdorf, Switzerland.

Because meltwater from the glaciers supplies the Fergana Valley, one of the largest irrigated areas on earth, the impact on farmers could be immense. The snow and glacier melt from Tien Shan also provides water to northern China, Kazakhstan, Uzbekistan, Turkmenistan and Kyrgyzstan. "It's like a huge water tower," says Farinotti.

Dramatic drop

The melt there is four times the global average, but rapid melting is no exception. Another study published earlier this month, which looked at the fate of all glaciers over the past century, excluding the troubled Greenland and Antarctic Ice sheets, which are affected by different dynamics, paints an equally gloomy picture.

"The first decade of the 21st century, from 2000 to 2010, saw the greatest decadal loss of glacier ice ever measured," says lead author Michael Zemp of the World Glacier Monitoring Service at the University of Zurich, Switzerland. "It's without precedent."

The analysis relied on 45,000 observations taken since 1894 of 2000 glaciers. Alarmingly, it shows that in the decade from 2001 to 2010, they lost on average 75 centimetres of their thickness each year.

This rate was twice the rate in the 1990s and treble that in the 1980s, demonstrating that the losses are accelerating fast.

"It means that globally, we're now losing treble the total ice volume of the European Alps each year," says Zemp. "We were shocked."

The largest retreats were seen in the European Alps, Alaska and the north-western areas of the US and Canada.

Global agreement

Zemp says that although the central Asian mountain study is more localised, it has tremendous value in validating the estimates and conclusions of the global study, which also found a prominent loss of ice in that area.

"It's perfect timing that our two studies have come out at the same time," says Zemp. "It gives us confidence that we can safely apply such measurements to all glaciers."

Farinotti used ground and meteorological data going back to 1961, and two types of satellite data between 2003 and 2009.

One type of satellite data relied on changes in gravity that depend on the mass of the glaciers, and the other relied on measuring the distance between the satellite and the surface of the glacier. When Farinotti compared the three methods, the estimates they gave of annual ice loss were remarkably close, averaging out at 5.4 gigatonnes per year.

The upshot is that the estimates of global glacier retreat, which mainly use historical ground data of ice thickness are likely to be accurate too, says Zemp. "They confirm at a regional level what we found at global level," he says.

The gloomiest news of all, says Farinotti, is that even if we halted emissions of carbon dioxide tomorrow, the glaciers would continue to melt for several decades because of the carbon dioxide already in the atmosphere.

Journal references: Nature Geoscience, DOI: 10.1038/ngeo2513; Journal of Glaciology, DOI: 10.3189/2015JoG15J017

l Nio has an 80 percent chance of lasting into early spring 2016, according to an updated forecast released on Thursday by the National Oceanic Atmospheric Adminisration (NOAA). NOAA also reported that there is a greater than 90 percent chance of El Nio lasting through the upcoming winter.

El Nio is an anomalous, yet periodic, warming of the central and eastern equatorial Pacific Ocean. For reasons still not well understood, every 2-7 years, this patch of ocean warms for six to 18 months.

The declaration that El Nio is likely to last into spring is important for the United States since precipitation and temperature impacts from a moderate-to-strong El Nio are typically most noticeable during the colder months. We have more on what those impacts are later in this article.

NOAA reports that sea-surface temperature anomalies increased in June in the equatorial Pacific Ocean. In addition, NOAA says that many computer models are predicting that sea-surface temperature anomalies will continue to increase through the fall.

Statistical and dynamical model forecasts from June 2015 of sea-surface temperature anomalies (degrees Celsius) until April 2016 in the region of the equatorial Pacific Ocean in which El Nino is defined. (IRI/CPC)

There's also an increasing chance El Nio may become strong, perhaps the strongest since the 1997-1998 episode and, thus, may play a stronger role in your weather.

WSI operational scientist Dr. Michael Ventrice tweeted Thursday the atmosphere continues to respond to the current El Nio in a similar fashion to the 1997-1998 event.

What does warm water have to do with the weather?

Schematic comparison of sea-surface temperature and most persistent rain/thunderstorm locations in neutral vs. El Nino conditions in the equatorial Pacific Ocean. (NOAA)

A 'Sea Change' in Atmospheric Circulation

Typically, easterly trade winds near the equator pile warm water into the western Pacific Ocean. Conversely, the resultant upwelling, or upward movement of deep, cold ocean water keeps the eastern and central Pacific Ocean cooler.

Thunderstorms require at least some degree of warm, humid air near the surface, so they're more numerous and persistent over the western Pacific warm pool, and much less so in the eastern equatorial Pacific.

During an El Nio, these trade winds weaken, and may at times reverse from west to east. Warmer western Pacific water then slowly sloshes back toward the central, even eastern Pacific Ocean in what's known as an equatorial-trapped Kelvin wave.

Therefore, the most persistent thunderstorms will shift from the western to the eastern and central Pacific Ocean in an El Nio.

This trade wind reversal and the resulting reorientation of thunderstorms changes the atmospheric circulation not just over this swath of the equatorial Pacific Ocean, but can also have far-reaching impacts on the atmospheric circulation.

Weather Impacts

First, keep two things in mind throughout this discussion of potential impacts:

1) El Nio is not the sole driver of the atmosphere at any time. Day-to-day variability in the weather pattern, including blocking patterns, forcing from climate change and other factors all work together with El Nio to determine the overall weather experienced over the timeframe of a few months.

2) No two El Nios are exactly alike. The intensity matters for impacts.

El Nio's clearest impact on northern hemisphere weather patterns occurs from late fall through winter.

Looking at past moderate-strong El Ninos, here are the upshots for temperatures and precipitation from late fall through winter in the U.S.:

- Wetter: Southern U.S. from California to the Carolinas then up parts of the East Coast

- Drier: Parts of the Ohio Valley, Great Lakes, Northwest and Northern Rockies

- Cooler: Desert Southwest, Southern Plains, northern Gulf Coast

- Warmer: Northern tier of states from the Pacific Northwest to the Northern Plains, Great Lakes, and Northeast

Note these are impacts that are typically expected, but they aren't always the rule.

Residents of the western states may remember the flooding that struck California during the strong 1997-98 El Nino. In February 1998, a series of storms caused an estimated $550 million in damage and killed 17 people in California. A total of 35 counties were declared federal disaster areas. This fits into the bucket of the wetter-than-average winter you would typically expect in a moderate or strong El Nio.

Interestingly, during the previous winter there was also major flooding in California and it was even more costly with a total price tag of $1.8 billion,according to Jan Null, a consulting meteorologist in California. However, El Nio was not present that winter and rainfall for the season was near average. The flooding was the result of excessive rainfall that fell in a short time period combined with snowmelt from late December to early January.

The weak El Nio in the winter of 2006-07 provided a totally different story than what we saw in the very strong 1997-98 El Nio winter.

California had its 23rd driest winter season on record when looking at the three-month period from December 2006 to February 2007. In Los Angeles, the entire water year from July 2006 to June 2007 was the driest on record with just 3.21 inches of rainfall.

So, those hoping for drought relief next winter in the Golden State shouldn't immediately draw a conclusion that significant rains are ahead in any El Nio year. The strength of the El Nio can play a role in the outcome. In addition, heavy rainfall can occur with or without El Nio present and that was the case in the winter preceding the strong 1997-1998 El Nio.

For the second time in what has been a frigid winter in the Northeastern United States, Niagara falls has come to an icy halt as the six million cubic feet of water that typically flow over the falls every minute has frozen over.

The flow of water over the falls typically can withstand icy temperatures like those that have frozen much of the country this winter, but Monday's high of 9 degrees Fahrenheit brought Niagara Falls to a standstill - and photographers were there to snap some stunning images of the frozen waterfall.

In January, another record-breaking cold front managed to freeze the mighty falls in a 'polar vortex' that turned the cascading water to ice - and affected about 240 million people in the U.S. and southern Canada.

No thaw is expected anytime soon, as temperatures at the western New York tourist attraction will dip below 0 degrees Fahrenheit Monday night through Tuesday morning.