Carbon Budget

This is a very clear analysis – upshot: humanity can burn a trillion tonnes of carbon before being committed to the 2°C warming limit governments have agreed. We’re 60% of the way there, and on course for 1.5 trillion, which would commit us to 3°C.

Azimuth

On Quora someone asked:

What is the most agreed-on figure for our future carbon budget?

My answer:

Asking “what is our future carbon budget?” is a bit like asking how many calories a day you can eat. There’s really no limit on how much you can eat if you don’t care how overweight and unhealthy you become. So, to set a carbon budget, you need to say how much global warming you will accept.

That said, here’s a picture of how we’re burning through our carbon budget:


It says that our civilization has burnt 60% of the carbon we’re allowed to while still having a 50-50 chance of keeping global warming below 2 °C.

This chart appears in the International Energy Agency report World Energy Outlook Special Report 2015, which is free and definitely worth reading.

The orange bars show CO2 emissions per year, in gigatonnes. The blue…

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The global warming hiatus could last another five years. Its aftermath is the real problem.

You may or may not know or care that the rate of increase in Earth’s average surface temperature has apparently eased off in recent years. A paper this week found that this ‘hiatus’ could go on for some years yet, but that it’s not that surprising, and definitely doesn’t mean we can stop worrying about climate change.

Of tree rings and rain: droughts predicted to worsen in southwestern United States

By the end of the 21st century, the average drought conditions in the Southwest US will exceed even the worst conditions during the megadroughts in the Medieval period

Good Night Earth

Figure courtesy of pixabay.com Figure courtesy of pixabay.com

Droughts have intensified in already dry regions around the world, including in the Southwest United States and in Australia throughout the first decade of this century.  The severity of these droughts has been attributed to global warming and climate change, which climate models predict should make traditional weather patterns more extreme, so dry regions will get drier.

However, there’s an inherent difficulty in determining the causes behind contemporary droughts because of their naturally long timescales.  During the medieval 12th and 13th centuries, North America experienced ‘megadroughts’ spanning 1000 years!  With such long timescales, it’s hard to know whether the intense dry spells we see now in California and nearby states are due to natural climatic variability or spurred on by anthropogenic carbon emissions.  Is man-made global warming to blame?

A recent paper in Science Advances provides a comprehensive answer to this question.  The group from…

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Climate researcher Bart Strengers wins wager with climate sceptic Hans Labohm

There has been some discussion of the accuracy of climate forecasts this week – this is an interesting reflection of the outcome when people of opposing viewpoints are prepared to bet on their position.

My view on climate change

Guestpost by Bart Strengers. Originally appeared as a news item on the PBL website.

Late 2009, in the run-up to the international climate conference in Copenhagen, PBL climate researcher Bart Strengers had an online discussion with climate sceptic Hans Labohm on the website of the Dutch news station NOS (in Dutch). This discussion, which was later also published as a PBL report, ended in a wager. Strengers wagered that the mean global temperature over the 2010–2014 period would be higher than the mean over 2000 to 2009. Hans Labohm believed there would be no warming and perhaps even a cooling; for example due to reduced solar activity.

At the request of Labohm, it was decided to use the UAH satellite temperature data set on the lower troposphere (TLT) (roughly the lowest 5 km of the atmosphere). These data sets are compiled by the University of Alabama in Huntsville…

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2014: A year in weather

According to the Met Office, 2014 was UK’s warmest since 1910, beating 2006 by 0.2°C. Central England Temperature also set to be the warmest in a series that dates back to 1659. It was also the fifth wettest year for the UK since 1910.

Official blog of the Met Office news team

2014 has been another year of eventful weather across the UK. Here we take a look at some of the year’s more notable aspects.

Temperature

The obvious headline from 2014 is that it will be the warmest year in our UK record dating back to 1910, knocking 2006 from its top spot.

Using figures up to 28 December then assuming average conditions for the last three days of the year, the expected mean temperature for the UK is 9.9 °C. This beats the previous record of 9.7 °C set in 2006 and means all the UK’s top eight warmest years have happened since 2002.

Despite the overall warmth, there were no record-breaking months – it’s just a case that 11 out of 12 months (August being the exception) were warmer than average. Although individual months were unremarkable, it was the persistence of the warmth that was unusual and together they add…

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A pause or not a pause, that is the question.

With 2014 looking set to be the warmest year ever (possibly by some way) I’ve been wondering what position the people claiming “global warming has stopped” might retreat to. This neat tale hints at one possibility, and explains why it wouldn’t be a convincing argument.

Open Mind

UPDATE: A new post at RealClimate is very relevant, and well worth the read.


One day, a new data set is released. The rumor runs rampant that it’s annual average global temperature since 1980.

artdat

Climate scientist “A” states that there is clearly a warming trend (shown by the red line), at an average rate of about 0.0139 deg.C/yr. She even computes the uncertainty in that trend estimate (using fancy statistics), and uses that to compute what’s called a “95% confidence interval” for the trend — the range in which we expect the true warming rate is 95% likely to be; it can be thought of as the “plausible range” for the warming rate. Since 95% confidence is the de facto standard in statistics (not universal, but by far the most common), nobody can fault her for that choice. The confidence interval is from 0.0098 to 0.0159 deg.C/yr. She also…

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United States and China reach landmark carbon emissions deal

The recent US-China climate deal seems to bode well for next December’s key talks: In case you missed it this is a good summary.

co2balance

B Barack Obama and Xi Jinping have agreed a deal on cutting emissions into the 2020s

The big news this morning is that the US and China have unveiled a “secretly negotiated deal” to reduce their greenhouse gas output, with China agreeing to cap emissions for the first time and the US committing to deep reductions by 2025. China, the biggest emitter of greenhouse gases in the world, has agreed to cap its emissions by 2030 or earlier if possible, and has also promised to increase its use of energy from zero-carbon sources to 20 per cent by 2030. The US has pledged to cut its emissions 26-28 per cent below 2005 levels by 2025.

Barack Obama said the deal was an “historic agreement”. China’s premier, Xi Jinping, said the US and China had agreed to make sure a global climate deal is reached in Paris next year.

  • Under the deal…

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