Benefits and costs of climate change

From Reuters (Climate change inaction will cost trillions):

Failing to fight global warming now will cost trillions of dollars by the end of the century even without counting biodiversity loss or unpredictable events like the Gulf Stream shutting down, a study said on Friday.

But acting now will avoid some of the massive damage and cost relatively little, said the study commissioned by Friends of the Earth from the Global Development and Environment Institute of Tufts University in the United States.

/.../

The study said the cost of inaction by governments and individuals could hit 11 trillion pounds a year by 2100, or six to eight percent of global economic output then. ... By contrast, spending just 1.6 trillion pounds a year now to limit temperature rises to two degrees could avoid annual economic damage of around 6.4 trillion pounds, the Tufts report said.

Here is the report: Climate Change - The Costs of Inaction [*.pdf].

Hat tip: Daily Grist.

Comments

[Will]

$3 trillion * (1.02)^100 = $19.3 trillion > $12 trillion

The real global economy grows by about 2% a year. By my figuring using the reports figures on page viii, global warming mitigation has a lower return than the economy at large. Why make the investment?

The next paragraph reports the present value of the costs, but it should report the discounted present value of mitigation investments, too. Or am I misreading that paragraph? Is it reporting the *net* present value?

[Dave D]

What is the price that will be paid in human lives? We see the effects already with the mass extinction of frogs and other amphibians all around the world. Unrelenting drought across US farmlands and across the whole continent of Australia, early winters and yearly record flooding in the Northeastern US are just the tip of the iceberg. There are many more examples, but I think it is clear that the weather patterns are changing, putting added stress on large population centers. Las Vegas, Phoenix and parts of Southern China will run out of water in 12-18 months. This is just the start of a shift in the jet stream and ocean currents that will alter weather patterns and force mass migrations. The raising seas will be minor compared to parched, burning forests in once prime wilderness and jungles.
Many permanent glaciers are already or nearly gone. The icecaps at the poles and in Greenland are shrinking rapidly. Many permanent snow packs on mountains are disappearing in China and Africa alarming local officials that say the rivers that feed them will dry up causing mass famine and the destruction of vast ecosystems. The financial cost will be huge no matter when or who pays it, but this it is a world wide problem and only world wide solutions will fix it. With the industrial revolution of the 21st century happening today in India and China, there will be a alarming potential for big increases in pollution output to occur. That with the US and European stubborn reluctance to change to greener ways this will only stall meaningful solutions, but we must start somewhere. It is in many ways too late. Whether man made or a natural cycle of the Earth's weather patterns, there will be heavy global consequences. There will be mass migrations of large populations to food and water sources. Whole cultures and civilizations will have to change the way they live. Wars are more likely when water supplies are at stake. Mass extinction of many species, which is already starting to occur, will mean the collapse of the many ecosystems which alone will destroy the survivability of all living things in particular areas. Without a doubt there will be many climate change related casualties. But either by violent weather or unending droughts we will surely see the changes take shape in our lifetimes and will pay the consequences

[Dave D]

Why are you splitting hairs over the cost. The ramifications of a change in global weather patterns transcend any discussion of cost. The cost does not matter if civilization is uprooted and the quality of life is severly impacted. Destruction of ecosystems may mean the demise of entire civilizations. These facts alone should diminish any discussion of cost. It's only a smoke screen for inaction. If you think this is a exaggeration, look at the world around you and compile the facts. They are overwhelming when compiled. Only a small minority of people believe it won't happen. The only question is when and how hard will it hit or is it a gradual phase in which would give us time to prepare and some species to adapt.