ALL YOU NEED TO KNOW ABOUT CLIMATE CHANGE By David Terry, author, the BEACONS on-line Guides to Climate Change. Free at Big ball of iron with some rock on the outside and a very very thin coating of moisture and oxygen and dangerous creatures - description of our planet in Wikipedia

Jean-Baptiste Joseph Fourier 1768 – 1830

Atmospheric CO2 concentration from 650,000 years ago to near present, using ice core proxy data and direct measurements. Global Climate Change -- Earth Science Communications Team at NASA's Jet Propulsion Laboratory/California Institute of Technology (data from NOAA) - This plots atmospheric CO2 concentration synthesizing ice core proxy data 650,000 years in the past capped by modern direct measurements.

Global mean land-ocean temperature change from 1880 to 2013, relative to the 1951–1980 mean. The black line is the annual mean and the red line is the 5-year running mean. The green bars show uncertainty estimates. Source: NASA GISS.running meanNASA GISS Global land temperatures have increased by 1.5 degrees C over the past 250 years Berkeley Earth has just released analysis of land-surface temperature records going back 250 years, about 100 years further than previous studies. The analysis shows that the rise in average world land temperature is approximately 1.5 degrees C in the past 250 years, and about 0.9 degrees in the past 50 years.

CO 2 levels, as measured at the Mauna Loa observatory fluctuate according to the month of the year but are increasing at a current rate of about 2.4ppm a year. This rate appears to be gradually increasing. ( ent-CO2/CO2- Now/global-co2- board.html ) ent-CO2/CO2- Now/global-co2- board.html

SEA LEVELS Since 1993, measurements from the TOPEX and Jason series of satellite radar altimeters have allowed estimates of global mean sea level. These measurements are continuously monitored against a network of tide gauges. When seasonal and other variations are subtracted, they allow estimation of the global mean sea level rate. As new data, models, and corrections become available, we continuously revise these estimates (about every two months) to improve their quality. 2014_rel5: Global Mean Sea Level Time Series (seasonal signals removed) Edited:

WHAT DO WE KNOW? How certain are we of each of the following? 1.CO 2 is a greenhouse gas. The amount in the atmosphere has increased steadily from about 280ppm in pre-industrial times to about 400ppm today 2.CO 2 emitted by burning fossil fuels remains in the atmosphere for at least 100 years 3.Other GHGs, notably water vapour and methane, have a stronger effects but remain for much shorter periods 4.Global temperatures have risen by about C in the last 100 years but since 1998 have risen only slightly 5.Sea levels have been rising for at least the last 150 years at a fairly steady 3.2 mm a year 6.The rise in temperatures and sea levels is largely a result of burning fossil fuels 7.If atmospheric CO 2 reaches 450ppm global temperatures are likely to exceed 2 0 C above those of 1900, and this will probably cause catastrophic climate change 8.The amount of CO 2 emitted by each country

WHAT SHOULD WE DO? 1.NOTHING – WAIT AND SEE 1.USE ENERGY MORE EFFICIENTLY 2.REDUCE CO 2 EMISSIONS 3.REDUCE THE USE OF FOSSIL FUELS OR CO 2 EMISSIONS FROM THEIR USE 4.PREPARE FOR A HOTTER PLANET 5.GEOENGINEERING

NOTHING – WAIT AND SEE 1.The hiatus in global temperature rise since 1998 makes future rise uncertain and we can afford to wait 2.Furthermore, the increase in atmospheric CO 2 is likely to be benign for several decades by stimulating plant growth 3.While action may be more expensive if delayed, future generations will be richer than we are and better able to afford necessary action 4.The longer we wait, the better the science and technology will be and the more effective any actions will be 5.Climate change is not the only potential threat to humanity. Before making it a top priority, it might be sensible to prioritise other threats such as a pandemic, an asteroid, a solar storm destroying the internet, Yellowstone eruption etc

USE ENERGY MORE EFFICIENTLY 1.Personal life styles 2.Transport 3.Industrial processes 4.Agriculture 5.Design of things 6.Consumption 7.Houses – heating and cooling

REDUCE CO 2 EMISSIONS Poor nations aspire to a similar life style to the rich. So they will want to use roughly the same amounts of energy. With an increasing world population, and despite increases in energy efficiency, this must mean at least a doubling of world energy consumption AN INTERNATIONAL TREATY TO REDUCE CO 2 EMISSIONS: WHAT’S THE PROBLEM?

DRASTICALLY REDUCE USE OF FOSSIL FUELS OR CO 2 EMISSIONS FROM THEIR USE 1.Increase energy efficiency 2.Renewables. Wind, wave, tidal, solar 3.Hydroelectric 4.Geothermal 5.Natural gas – fracking 6.Carbon capture and storage 7.Biomass 8.Nuclear fission 9.Nuclear fusion

PREPARE FOR A HOTTER PLANET 1.Drought-resistant plants, including GM 2.Computer-controlled irrigation 3.Water management 4.Desalination 5. Migration of mosquitoes etc 6.Move or protect low-lying habitation 7.Cope with vast population migrations

GEOENGINEERING 1.Geoengineering to cool the planet 2.Geoengineering to remove CO 2 and other GHGs

WHAT IF THE PLANET BECOMES UNINHABITABLE? Suppose that, despite all efforts, runaway and irreversible global warming occurs. The polar ice sheets melt ever more rapidly, sea levels rise by a metre or so a year overwhelming sea walls and barriers, deserts cover more and more of the land, mass migrations and severe water shortages lead to terrible conficts

THE FINAL OPTION

Letter in the Financial Times March 18 th 2014