December 14, 2017

The Reality of Climate Change

It is now common knowledge that global temperatures have increased, and according to the Intergovernmental Panel on Climate Change (IPCC), the global mean surface temperature has increased by about 0.07oC per decade in the last century.

However, in the last 25 years, temperatures have risen faster about 0.18oC per decade with the last decade (2001-2010) being the warmest on record. The average temperature over this period is 0.46oC more than the 1961-1990 mean, and 0.21oC warmer than previous decades. This is consistent with a long term warming trend.

As a result of the increase in global temperatures, the global average sea level has risen since 1961 at an average rate of 1.8 mm per year, and since 1993 at 3.1 mm per year. At the same time, there has been a significant increase in precipitation in the southern parts of North and South America, northern Europe and northern and central Asia. While these regions are experiencing heavy precipitation events, others including the Sahel, the Mediterranean, South Africa and parts of south Asia are experiencing dry conditions. 

Decadal global average combined land-ocean surface temperature (°C), redrawn from WMO, 2011

 Changes in extreme weather conditions have also been recorded. For instance, cold days, cold nights and frost are less frequent, while hot days, hot nights, and heat waves are more frequent.  Intense and longer spells of droughts have also been observed since the 1970s, especially in the tropics and subtropics.

Most parts of Africa have experienced changes in weather patterns in the past few decades. Temperature increase across the continent has been recorded since the 1960s with 2010 being the warmest year on record in Africa, particularly, for West Africa, the Sahara/Arabian region, and the Mediterranean. In 2010, average temperatures recorded over Africa were 1.29oC more than the long term average. On the whole, the continent has been drier in the few past decades, but while rainfall has decreased in some regions, other regions have experienced an increase. For example, during the period from 1961-1990, rainfall dropped in the horn of Africa, Botswana, Zimbabwe, the Transvaal, and the Sahel. On the other hand, a significant increase in rainfall has been reported in South Africa and in the Volta Basin. Central Africa (Congo basin) also experienced a drop of 2-3% in precipitation, but heavy rainfall events increased over Angola, Namibia, Mozambique, Malawi, and Zambia between 1931 and 1990.

For the past 30 years, the frequency of extreme climatic conditions have increased in Africa. The severity and rate of occurrence of droughts have increased in Eastern Africa, where droughts have occurred in each decade over the past 50 years. Droughts have become more frequent in Central Africa and the Sahel since the late 1960s. Conversely, an increase in rainfall extremes has been observed in Southern Africa and the Guinean Coast with an increase in the frequency of rain days and heavy rains often accompanied by severe floods. The southern part of Nigeria has also experienced devastating floods in the last five decades.

The frequent occurrence of these extreme climatic events is due to the increase in Green House Gases (GHGs) in the atmosphere, which is significantly altering the earth’s climate. Although the more developed countries are largely responsible for the increase in GHGs, Africa also contributes to the increase in various but minute ways. These include deforestation, release of black carbon (including gas flaring and bush burning), methane from waste (improper waste management) and other industrial activities.

climate-change (2)

Africa’s vulnerability to climate change and variability are mainly due to the following reasons:

  • Many poor communities in Africa tend to have a higher share of their assets and wealth tied up in natural resources, so anything that damages the natural resource base will certainly have a negative impact on these communities and their countries.
  • The lack of irrigation facilities and the reliance on rainfall by most farmers in Africa is making crop production highly vulnerable to even slight changes in rainfall patterns.
  • One third of Africa’s productive area is already classified as dry land, and climate change may bring less rainfall and a shorter growing season, extending such dry lands over a larger area.
  • Most governments and institutions are weak and inadequately resourced, so those vulnerable to climate change would have to find ways to cope on their own, and the brain drain on the few well-qualified people further limits capacity African countries.
  • Most people operate at low levels of income with limited reserves, and lack formal insurance cover.

What is the damage and the way forward?……..To be continued


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