11.12.2012 Views

Full colour version of the BP magazine

Full colour version of the BP magazine

Full colour version of the BP magazine

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

“Thanks to <strong>the</strong> growth in computing power, better<br />

methods <strong>of</strong> data collection and handling – and, most<br />

importantly, increased brain power – we now know more<br />

about <strong>the</strong> climate system than we did 10 years ago.”<br />

Dr V Ramaswamy<br />

incorporate ‘what if’ scenarios – to gain an<br />

idea <strong>of</strong> how <strong>the</strong> climate may behave if, for<br />

example, oceanic or atmospheric<br />

conditions change.”<br />

With so many processes and scenarios<br />

to consider, developing and running <strong>the</strong><br />

models is a major challenge, as is<br />

interpreting <strong>the</strong> results. Both wea<strong>the</strong>r and<br />

climate are subject to natural variations,<br />

which have nothing to do with <strong>the</strong> forcing<br />

that drives climate change. Sorting out<br />

those variations from <strong>the</strong> effects <strong>of</strong> forcing<br />

requires a major effort. Ironically, says Dr<br />

Ramaswamy, “although we are still not able<br />

to reliably predict climate variability with<br />

our modelling, we can use it to study <strong>the</strong><br />

effect <strong>of</strong> <strong>the</strong> forced variations in order to<br />

get a good handle on how <strong>the</strong> global<br />

climate will change over a timescale <strong>of</strong><br />

decades. And we can also get a good idea <strong>of</strong><br />

what is causing <strong>the</strong> changes.”<br />

Temperature records reveal that during<br />

<strong>the</strong> 20th century <strong>the</strong> climate system as a<br />

whole had warmed. The model results<br />

confirm that most <strong>of</strong> this global warming<br />

can be attributed to observed increases in<br />

concentrations <strong>of</strong> greenhouse gases. These<br />

rises have been strongly influenced by<br />

human activity, with <strong>the</strong> continuous rise in<br />

anthropogenic – or human-generated –<br />

CO2 levels responsible for about 55% <strong>the</strong><br />

warming effect.<br />

But climate modelling is not all doom<br />

and gloom. It is also useful in exploring <strong>the</strong><br />

options for adapting to, and mitigating <strong>the</strong><br />

effects <strong>of</strong>, climate change. The information<br />

derived from climate modelling is already<br />

being used to clarify <strong>the</strong> options policy<br />

makers need to understand in order to<br />

make <strong>the</strong> right choices to prevent fur<strong>the</strong>r<br />

environmental damage. Climate modelling<br />

results will, for example, play an important<br />

role in a two-year study focusing on climate<br />

change and climate choices, beginning at<br />

<strong>the</strong> US National Academy <strong>of</strong> Sciences.<br />

There are a number <strong>of</strong> scientificallybased<br />

options – for example, carbon<br />

capture and sequestration, or planting<br />

more forests – under consideration. “But<br />

whe<strong>the</strong>r <strong>the</strong>se are <strong>the</strong> best options and<br />

whe<strong>the</strong>r <strong>the</strong>y are economically feasible,”<br />

says Dr Ramaswamy, “is ano<strong>the</strong>r question.<br />

Technology> Climate modelling<br />

Developing mitigation strategies for global<br />

warming is – like understanding climate<br />

change itself – a great balancing act, and<br />

decisions must be taken with great care.”<br />

The good news is that <strong>the</strong> technology<br />

for climate modelling continues to<br />

improve. “By developing better ways to<br />

analyse data more intelligently, climate<br />

modellers are increasing our quantitative<br />

understanding <strong>of</strong> how climate works.<br />

Thanks to <strong>the</strong> growth in computing power,<br />

better methods <strong>of</strong> data collection and<br />

handling – and, most importantly,<br />

increased brain power – we know more<br />

about <strong>the</strong> climate system than we did 10<br />

years ago, and this is being fed back in to<br />

improve our understanding even fur<strong>the</strong>r.<br />

Climate modellers have already unravelled<br />

many aspects <strong>of</strong> <strong>the</strong> climate system and<br />

contributed useful information to help <strong>the</strong><br />

world adapt to or mitigate climate change.<br />

Thanks to continuing incremental<br />

advances in observation technology,<br />

coupled with ever-growing computing<br />

power, we’re learning more all <strong>the</strong> time.” ■<br />

Wea<strong>the</strong>r and climate:<br />

what’s <strong>the</strong> difference?<br />

Wea<strong>the</strong>r refers to <strong>the</strong> state <strong>of</strong><br />

atmospheric conditions, such as<br />

humidity, precipitation, temperature,<br />

cloud cover and wind at any one place<br />

at any one time. Climate, in contrast,<br />

refers to <strong>the</strong> characteristic pattern <strong>of</strong><br />

wea<strong>the</strong>r elements over several decades.<br />

Wea<strong>the</strong>r forecasting and climate<br />

modelling generally rely on <strong>the</strong> same<br />

sort <strong>of</strong> data – but treat <strong>the</strong>m in<br />

different ways. The goals are different,<br />

too. For wea<strong>the</strong>r forecasting, <strong>the</strong> aim is<br />

to predict accurately what <strong>the</strong> wea<strong>the</strong>r<br />

will be like a few days in <strong>the</strong> future.<br />

With climate modelling, <strong>the</strong> challenge<br />

is to predict how climate systems will<br />

behave and what will influence <strong>the</strong>ir<br />

behaviour decades into <strong>the</strong> future.<br />

<strong>BP</strong> MAGAZINE Issue 1 2009 51

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!