A German expert called for strengthened actions against global warming Friday, days before the United Nations Climate Change Conference in Doha next week. \"With the current pledges made by countries and their measures, we are on the course of 3.5 or 4 degrees Celsius warming towards the end of the century,\" said professor Hans Joachim Schellnhuber, director of Potsdam Institute for Climate Impact Research (PIK). \"We have to avoid that,\" urged Schellnhuber, who is also the Chairman of German Advisory Council on Global Change, an advisory body for German federal government. \"A four-degree-Celsius-increase world would be one of unprecedented heat waves, severe drought, and major floods in many regions, with serious impacts on ecosystems and associated services,\" warned a report conducted by PIK and Berlin-based Climate Analytics for the World Bank. In Copenhagen Climate Change Conference 2009, the target of global warming by 2100 was set at below 2 degrees Celsius, compared with the level in the pre-industrialization time. Representatives from nearly 200 countries will gather at Doha next week for the 18th Conference of Parties to United Nations Framework Convention on Climate Change. \"We have technical means for the goal of 2 degrees Celsius, we have probably even the money for doing that, but we do not have the political will so far,\" said Schellnhuber. At the Climate Change Conference 2011 in Durban, South Africa, parties agreed to start from 2013 the second commitment period of Kyoto Protocol, the only legally binding treaty for emission reduction currently. A protocol, another legal instrument or an agreed outcome with legal force under the Convention applicable to all parties, was also decided to be set no later than 2015 and to be implemented from 2020. The following two climate change negotiations this year in Bonn, Germany and Bangkok, Thailand, however, failed to see progress in agreement on climate protection. Developed and developing countries could not reach consensus either on the length of the second commitment period or even the principle to which should be respected in the new legal instrument set to come into force from 2020. \"If we cannot solve this problem today, we will solve it in ten years, but in ten years, it will be too late,\" said Schellnhuber, \"you cannot negotiate with nature, while we are quarreling, nature will just march on.\"